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Firewalld setup that allows only selected IPs or subnets for services like ssh

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Firewalld is a firewall management solution available In RHEL and its clones, which acts as a frontend for the iptables packet filtering system provided by the Linux kernel. The firewalld service allows you to configure maintainable rules and rule-sets that take into consideration your network environment. It allows you to seamlessly transition between different firewall policies nased on IIP/service combinations gives administrators the ability to abstract the port management into more higher level concept of zones.

It is not easy how to set up a firewall for your server, especially in complex environment like Azure

Command like utility firewall-cmd is used as the administrative tool for firewalld daemon (if you'd rather use iptables with CentOS6, follow this guide ).

Firewalld operates using the concept of zones, which in principle are similar to security zones what were used in IE 11.  IPs and subnets can be assigned to particular zones. Some zones have IP range they cover predefined.  Some have some additional capabilities predefined.

NOTE:

filewalld has XML config file which can be edited directly. This is often simpler then trying to understand arcane commands of  firewall-cmd

Looks like systemd people in Red Hat are closet sadists and like to torture sysadmins with excessive complexity.

The trick is to remove default services like sshd from public zone and define them in internal zone (zone used for remote administration), for which you need to provide the list of IP and subnets using  IP sets.

On Azure to preserve compatibility you also need to define your 10 network as trusted zone.

The best explanation of how to do it that I have found was in the answer to the post  command line interface - block all but a few ips with firewalld - Server Fault. Below is a slightly modified write from this post.

It is not necessary to use rich rules in most cases. If you want to restrict a access for set of specific set of IPs, or subnets, it is simpler define those IPs as sources for a zone other then public

(and remove any interface definition that may be present, as they override source IPs).

Do not use the "public" zone for restricting acess to particular services based on IPs. Semantically public zone means the set of services open to the world (it can none)

Instead, try using a different zone such as "internal" for "mostly trusted" IP addresses (addresses used to administer the serveror VM) and add to it sshd and other sensitive services

Warning:

Don't mistake the special "trusted" zone with the normal "internal" zone. Any sources added to the "trusted" zone will be allowed through on all ports; adding services to "trusted" zone is allowed but it doesn't make any sense to do so. In Azure 10 network can be made trusted as this is an internal network.

For example:

firewall-cmd --zone=internal --add-service=ssh
firewall-cmd --zone=internal --add-source=168.199.0.0/16 # subnet for administration -- possibly from your home PC
firewall-cmd --zone=trusted --add-source=10.0.3.0/24 # Azure internal network 
firewall-cmd --zone=public --remove-service=ssh

The result of this will be a "internal" zone which permits access to ssh, but only from the specified subnet. To make it persistent, re-run each command with --permanent appended, or better, by using firewall-cmd --runtime-to-permanent.

NOTE:  you could create an  IP set  for a non-contiguous list of allowed IPs.

Runtime and Permanent Settings

Any changes committed in runtime mode only apply while firewalld is running. When firewalld is restarted, the settings revert to their permanent values.

To make the changes persistent across reboots, apply them again using the --permanent option. Alternatively, to make changes persistent while firewalld is running, use the --runtime-to-permanent firewall-cmd option.

If you set the rules while firewalld is running using only the --permanent option, they do not become effective before firewalld is restarted. However, restarting firewalld closes all open ports and stops the networking traffic.

To change settings in both modes, you can use two methods:

  1. Change runtime settings and then make them permanent as follows. In this case you can use --timeout
    # firewall-cmd <other options>
    # firewall-cmd --runtime-to-permanent # NOTE: firewall-cmd --reload command issued after after would be redundant unless you used --timeout option 
  2. Set permanent settings and reload the settings into runtime mode. I so not recommend that because using the --permanent option prevents using  the --timeout option which is very useful if you connects tot he server remotely as it prevent locking yourself out.
    # firewall-cmd --permanent <other options>
    # firewall-cmd --reload

NOTES:

Here is a useful explanation of the concepts of zones adapted from How To Set Up a Firewall Using FirewallD on CentOS 7 By Justin Ellingwood

Zones

The firewalld daemon operated using the concept of the groups of rules called "zones". The predefined zones are stored in the /etc/firewalld/zones/ and can be edited directly as they represents XML files in the /etc/filewalld directory.

Zones are basically sets of rules dictating what traffic should be allowed depending on the level of trust you have for the particular part of your IP space.

Zones are basically sets of predefined rules dictating what traffic should be allowed depending. They differ by the level of trust you have in the networks your computer is connected to.

Network interfaces are assigned a zone to dictate the behavior that the firewall should allow.

 In a way this concept is similar to security zones that were used in IE 11. Each zone is defined iether by subnet (which by default is  0.0.0.0/0 for public; more restricted for internal and other zones that are used) or interface if no subnet is specified.

Network interfaces can be assigned to zones to dictate the behavior that the firewall should allow. But it makes sense mostly when you have multiple interfaces.

Selection of the zone involve both but it is unclear how.  In any case if connection comes from the interface assigned to the public zone (for example Wifi) all protocol which are not defined in this zone are dropped.  But logically interface pays a role if and only if zone encompass all IP space. It IP space is restricted (as it is typically for internal zone) it became the defining factor as for which protocols are allowed (for internal zone sshd is typically allowed, but for public it is not)

Of interface is not defines then IP rules are to select zone to which particular connection belongs.

For computers that might move between networks frequently (like laptops), this kind of flexibility provides a good method of changing your rules depending on your environment. You may have strict rules in place prohibiting most traffic when operating on a public WiFi network, while allowing more relaxed restrictions when connected to your home network. For a server, these zones are not as immediately important because the network environment rarely, if ever, changes.

Regardless of how dynamic your network environment may be, it is still useful to be familiar with the general idea behind each of the predefined zones for firewalld . In order from least trusted to most trusted , the predefined zones within firewalld are:

To use the firewall, we can create rules and alter the properties of our zones and then assign our network interfaces to whichever zones are most appropriate.

Rule Permanence

In firewalld, rules can be designated as either permanent or immediate. If a rule is added or modified, by default, the behavior of the currently running firewall is modified. At the next reboot, the changes will be discards and old rules will be loaded.

Most firewall-cmd operations can take the --permanent flag to indicate that the non-ephemeral firewall should be targeted. This will affect the rule set that is reloaded upon boot. This separation means that you can test rules in your active firewall instance and then reload if there are problems.

NOTE: do not use --permanent flag is you are configuring firewall from a remote location.

Install and Enable Your Firewall to Start at Boot

firewalld is installed by default on some Linux distributions, including many images of CentOS 7. However, it may be necessary for you to install firewalld yourself:

sudo yum install firewalld

After you install firewalld , you can enable the service and reboot your server. Keep in mind that enabling firewalld will cause the service to start up at boot. It is best practice to create your firewall rules and take the opportunity to test them before configuring this behavior in order to avoid potential issues.

sudo systemctl enable firewalld
sudo reboot

When the server restarts, your firewall should be brought up, your network interfaces should be put into the zones you configured (or fall back to the configured default zone), and any rules associated with the zone(s) will be applied to the associated interfaces.

We can verify that the service is running and reachable by typing:

sudo firewall-cmd --state
output running

This indicates that our firewall is up and running with the default configuration.

Exploring the Defaults

Before we begin to make modifications, we should familiarize ourselves with the default environment and rules provided by the daemon.

We can see which zone is currently selected as the default by typing:

firewall-cmd --get-default-zone
This should output public

Since we haven't given firewalld any commands to deviate from the default zone, and none of our interfaces are configured to bind to another zone, that zone will also be the only "active" zone (the zone that is controlling the traffic for our interfaces). We can verify that by typing:

firewall-cmd --get-active-zones
output public interfaces: eth0 eth1

Here, we can see that our example server has two network interfaces being controlled by the firewall ( eth0 and eth1 ). They are both currently being managed according to the rules defined for the public zone.

How do we know what rules are associated with the public zone though? We can print out the default zone's configuration by typing:

We can tell from the output that this zone is both the default and active and that the eth0 and eth1 interfaces are associated with this zone (we already knew all of this from our previous inquiries). However, we can also see that this zone allows for the normal operations associated with a DHCP client (for IP address assignment) and SSH (for remote administration).

Exploring Alternative Zones

Now we have a good idea about the configuration for the default and active zone. We can find out information about other zones as well.

To get a list of the available zones, type:

firewall-cmd --get-zones
output
block dmz drop external home internal public trusted work

We can see the specific configuration associated with a zone by including the --zone= parameter in our --list-all command:

sudo firewall-cmd --zone= home --list-all
output home interfaces: sources: services: dhcpv6-client ipp-client mdns samba-client ssh ports: masquerade: no forward-ports: icmp-blocks: rich rules:

You can output all of the zone definitions by using the --list-all-zones option. You will probably want to pipe the output into a pager for easier viewing:

sudo firewall-cmd --list-all-zones | less

Selecting Zones for your Interfaces

Unless you have configured your network interfaces otherwise, each interface will be put in the default zone when the firewall is booted.

You can transition an interface between zones during a session by using the --zone= parameter in combination with the --change-interface= parameter. As with all commands that modify the firewall, you will need to use sudo .

For instance, we can transition our eth0 interface to the "home" zone by typing this:

sudo firewall-cmd --zone=home --change-interface=eth0
output success Note Whenever you are transitioning an interface to a new zone, be aware that you are probably modifying the services that will be operational. For instance, here we are moving to the "home" zone, which has SSH available. This means that our connection shouldn't drop. Some other zones do not have SSH enabled by default and if your connection is dropped while using one of these zones, you could find yourself unable to log back in.

We can verify that this was successful by asking for the active zones again:

firewall-cmd --get-active-zones
output home interfaces: eth0 public interfaces: eth1

Adjusting the Default Zone

If all of your interfaces can best be handled by a single zone, it's probably easier to just select the best default zone and then use that for your configuration. You can change the default zone with the --set-default-zone= parameter. This will immediately change any interface that had fallen back on the default to the new zone:

sudo firewall-cmd --set-default-zone= home
output success Setting Rules for your Applications

The basic way of defining firewall exceptions for the services you wish to make available is easy. We'll run through the basic idea here.

Adding a Service to your Zones

The easiest method is to add the services or ports you need to the zones you are using. Again, you can get a list of the available services with the --get-services option:

firewall-cmd --get-services

You can get more details about each of these services by looking at their associated .xml file within the /usr/lib/firewalld/services directory. For instance, the SSH service is defined like this:

/usr/lib/firewalld/services/ssh.xml
<?xml version="1.0" encoding="utf-8"?>
<service>
  <short>SSH</short>
  <description>Secure Shell (SSH) is a protocol for logging into and executing commands on remote machines. It provides secure encrypted communications. If you plan on accessing your machine remotely via SSH over a firewalled interface, enable this option. You need the openssh-server package installed for this option to be useful.</description>
  <port protocol="tcp" port="22"/>
</service>

You can enable a service for a zone using the --add-service= parameter. The operation will target the default zone or whatever zone is specified by the --zone= parameter. By default, this will only adjust the current firewall session. You can adjust the permanent firewall configuration by including the --permanent flag.

For instance, if we are running a web server serving conventional HTTP traffic, we can allow this traffic for interfaces in our "public" zone for this session by typing:

sudo firewall-cmd --zone=public --add-service=http

You can leave out the --zone= if you wish to modify the default zone. We can verify the operation was successful by using the --list-all or --list-services operations:

sudo firewall-cmd --zone=public --list-services
output dhcpv6-client http ssh

Once you have tested that everything is working as it should, you will probably want to modify the permanent firewall rules so that your service will still be available after a reboot. We can make our "public" zone change permanent by typing:

sudo firewall-cmd --zone=public --permanent --add-service=http
output success

You can verify that this was successful by adding the --permanent flag to the --list-services operation. You need to use sudo for any --permanent operations:

sudo firewall-cmd --zone=public --permanent --list-services
output dhcpv6-client http ssh

Your "public" zone will now allow HTTP web traffic on port 80. If your web server is configured to use SSL/TLS, you'll also want to add the https service. We can add that to the current session and the permanent rule-set by typing:

sudo firewall-cmd --zone=public --add-service=https
sudo firewall-cmd --zone=public --permanent --add-service=https

What If No Appropriate Service Is Available?

The firewall services that are included with the firewalld installation represent many of the most common requirements for applications that you may wish to allow access to. However, there will likely be scenarios where these services do not fit your requirements.

In this situation, you have two options.

Opening a Port for your Zones

The easiest way to add support for your specific application is to open up the ports that it uses in the appropriate zone(s). This is as easy as specifying the port or port range, and the associated protocol for the ports you need to open.

For instance, if our application runs on port 5000 and uses TCP, we could add this to the "public" zone for this session using the --add-port= parameter. Protocols can be either tcp or udp :

sudo firewall-cmd --zone=public --add-port=5000/tcp
output success

We can verify that this was successful using the --list-ports operation:

sudo firewall-cmd --zone=public --list-ports
output 5000/tcp

It is also possible to specify a sequential range of ports by separating the beginning and ending port in the range with a dash. For instance, if our application uses UDP ports 4990 to 4999, we could open these up on "public" by typing:

sudo firewall-cmd --zone=public --add-port=4990-4999/udp

After testing, we would likely want to add these to the permanent firewall. You can do that by typing:

sudo firewall-cmd --zone=public --permanent --add-port=5000/tcp
sudo firewall-cmd --zone=public --permanent --add-port=4990-4999/udp
  • sudo firewall-cmd --zone=public --permanent --list-ports

    output success success 5000/tcp 4990-4999/udp

    Defining a Service

    Opening ports for your zones is easy, but it can be difficult to keep track of what each one is for. If you ever decommission a service on your server, you may have a hard time remembering which ports that have been opened are still required. To avoid this situation, it is possible to define a service.

    Services are simply collections of ports with an associated name and description. Using services is easier to administer than ports, but requires a bit of upfront work. The easiest way to start is to copy an existing script (found in /usr/lib/firewalld/services ) to the /etc/firewalld/services directory where the firewall looks for non-standard definitions.

    For instance, we could copy the SSH service definition to use for our "example" service definition like this. The filename minus the .xml suffix will dictate the name of the service within the firewall services list:

    sudo cp /usr/lib/firewalld/services/ssh.xml /etc/firewalld/services/ example .xml

    Now, you can adjust the definition found in the file you copied:

    sudo vi /etc/firewalld/services/example.xml
    

    To start, the file will contain the SSH definition that you copied:

    /etc/firewalld/services/example.xml
    <?xml version="1.0" encoding="utf-8"?>
    <service>
      <short>SSH</short>
      <description>Secure Shell (SSH) is a protocol for logging into and executing commands on remote machines. It provides secure encrypted communications. If you plan on accessing your machine remotely via SSH over a firewalled interface, enable this option. You need the openssh-server package installed for this option to be useful.</description>
      <port protocol="tcp" port="22"/>
    </service>

    The majority of this definition is actually metadata. You will want to change the short name for the service within the <short> tags. This is a human-readable name for your service. You should also add a description so that you have more information if you ever need to audit the service. The only configuration you need to make that actually affects the functionality of the service will likely be the port definition where you identify the port number and protocol you wish to open. This can be specified multiple times.

    For our "example" service, imagine that we need to open up port 7777 for TCP and 8888 for UDP. By entering INSERT mode by pressing i , we can modify the existing definition with something like this:

    /etc/firewalld/services/example.xml
    <?xml version="1.0" encoding="utf-8"?>
    <service>
      <short>Example Service</short>
      <description>This is just an example service.  It probably shouldn't be used on a real system.</description>
      <port protocol="tcp" port="7777"/>
      <port protocol="udp" port="8888"/>
    </service>
    

    Press ESC , then enter :x to save and close the file.

    Reload your firewall to get access to your new service:

    sudo firewall-cmd --reload

    You can see that it is now among the list of available services:

    firewall-cmd --get-services

    You can now use this service in your zones as you normally would.

    Creating Your Own Zones

    While the predefined zones will probably be more than enough for most users, it can be helpful to define your own zones that are more descriptive of their function. For example

    sudo firewall-cmd  --new-zone=fireeye
    sudo firewall-cmd --zone=fireeye --add-service=http
    sudo firewall-cmd --zone=fireeye --add-service=http
    sudo firewall-cmd --zone=fireeye --add-service=https
    firewall-cmd --zone=fireeye --add-source 10.6.1.1
    firewall-cmd --zone=fireeye --add-source 10.6.1.2
    sudo firewall-cmd --reload

    Another example is the zone for HTTP and HTTPS services. We can call it "publicweb". However, you might want to have another zone configured so that only selected IPs can access it. Let's call it "privatweb". Similarly you can have zone "privatedns" for your DNS servers.

    When adding a zone, you must add it to the permanent firewall configuration. You can then reload to bring the configuration into your running session. For instance, we could create the two zones we discussed above by typing:

    sudo firewall-cmd --permanent --new-zone=publicweb
    sudo firewall-cmd --permanent --new-zone=privatedns

    You can verify that these are present in your permanent configuration by typing:

    sudo firewall-cmd --permanent --get-zones
    output block dmz drop external home internal privatedns public publicweb trusted work

    As stated before, these won't be available in the current instance of the firewall yet:

    firewall-cmd --get-zones
    output block dmz drop external home internal public trusted work

    Reload the firewall to bring these new zones into the active configuration:

    sudo firewall-cmd --reload
    firewall-cmd --get-zones
    output block dmz drop external home internal privatedns public publicweb trusted work

    Now, you can begin assigning the appropriate services and ports to your zones. It's usually a good idea to adjust the active instance and then transfer those changes to the permanent configuration after testing. For instance, for the "publicweb" zone, you might want to add the SSH, HTTP, and HTTPS services:

    sudo firewall-cmd --zone=publicweb --add-service=ssh
    sudo firewall-cmd --zone=publicweb --add-service=http
    sudo firewall-cmd --zone=publicweb --add-service=https
    sudo firewall-cmd --zone=publicweb --list-all
    output publicweb target: default icmp-block-inversion: no interfaces: sources: services: ssh http https ports: protocols: masquerade: no forward-ports: source-ports: icmp-blocks: rich rules:

    Likewise, we can add the DNS service to our "privatedns" zone:

    sudo firewall-cmd --zone=privatedns --add-service=dns
    sudo firewall-cmd --zone=privatedns --list-all
    output privatedns interfaces: sources: services: dns ports: masquerade: no forward-ports: icmp-blocks: rich rules:

    We could then change our interfaces over to these new zones to test them out:

    sudo firewall-cmd --zone=publicweb --change-interface=eth0
    sudo firewall-cmd --zone=privatedns --change-interface=eth1

    At this point, you have the opportunity to test your configuration. If these values work for you, you will want to add the same rules to the permanent configuration. You can do that by re-applying the rules with the --permanent flag:

    sudo firewall-cmd --zone=publicweb --permanent --add-service=ssh
    sudo firewall-cmd --zone=publicweb --permanent --add-service=http
    sudo firewall-cmd --zone=publicweb --permanent --add-service=https
    sudo firewall-cmd --zone=privatedns --permanent --add-service=dns

    After permanently applying these your rules, you can restart your network and reload your firewall service:

    sudo systemctl restart network
    sudo systemctl reload firewalld

    Validate that the correct zones were assigned:

    firewall-cmd --get-active-zones
    output privatedns interfaces: eth1 publicweb interfaces: eth0

    And validate that the appropriate services are available for both of the zones:

    sudo firewall-cmd --zone=publicweb --list-services
    output http https ssh
    sudo firewall-cmd --zone=privatedns --list-services
    output dns

    You have successfully set up your own zones! If you want to make one of these zones the default for other interfaces, remember to configure that behavior with the --set-default-zone= parameter:

    sudo firewall-cmd --set-default-zone=publicweb
    

     

    Typical blunders

    How do I get firewalld to restrict access to all except specified IP addresses?

    Here the guy did a typical mistake trying to restrict public zone instead of defining necessary services and IPs in internal zone

    I would appreciate some assistance with configuring firewalld please. Here's a bit of background. All I want to do is prevent all access- except whitelisted IP addresses to a web application running on https.

    I have done much googling. learnt a number of things but none has worked yet. Here's what I have done:

    1. I can tell firewalld is running
      # systemctl status firewalld
      
      firewalld.service - firewalld - dynamic     firewall daemon    Loaded: loaded
      (/usr/lib/systemd/system/firewalld.service; enabled)    Active: active
      (running)
      

    also with

        # firewall-cmd --state
        running
    
    1. I have the default zones
      # firewall-cmd --get-zones
      block dmz drop external home internal public trusted work
      
    2. My active zones include:
      # firewall-cmd --get-active-zones
      public
      sources: 192.72.0.193 192.72.0.0/22 94.27.256.190
      
    3. My default zone is public:
      # firewall-cmd --get-default-zone
      public
      
    4. The details of public are:
      public (default)  
      interfaces:  
      sources: 192.72.0.193 192.72.0.0/22 94.27.256.190  
      services: http https ssh  
      ports:  
      masquerade: no  
      forward-ports:  
      icmp-blocks:  
      rich rules:
      

    My understanding is that the configuration for public zone above will restrict only grant to requests from any of the specified IP addresses. However, when I try accessing https://www.example.com from an IP outside the listed, it allows it. iptables redhat centos7 firewalld share improve this question follow edited Apr 16 '15 at 22:32

    dawud 14.2k 3 3 gold badges 38 38 silver badges 59 59 bronze badges asked Apr 16 '15 at 11:36

    pi. 219 3 3 silver badges 8 8 bronze badges

  • That looks right. Have you got other zones? – Michael Hampton Apr 16 '15 at 17:33
  • See this post for more options: serverfault.com/questions/680780/zaadman Nov 25 '16 at 23:36 add a comment

    1 Answer Active Oldest Votes 2

    one option is to remove the service: https from the zone

    firewall-cmd --zone=public --remove-service=https

    and then use what is known as rich rules to specify what sources [IP addresses] may access what service [such as http and https] like so:

    firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="x.x.x.0/24" service name="https" log prefix="https" level="info" accept'
    

    might need to reload though


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    Old News ;-)

    [Sep 14, 2020] How to Open Port for a Specific IP Address in Firewalld

    Sep 14, 2020 | www.tecmint.com

    How can I allow traffic from a specific IP address in my private network or allow traffic from a specific private network through firewalld , to a specific port or service on a Red Hat Enterprise Linux ( RHEL ) or CentOS server?

    In this short article, you will learn how to open a port for a specific IP address or network range in your RHEL or CentOS server running a firewalld firewall.

    The most appropriate way to solve this is by using a firewalld zone. So, you need to create a new zone that will hold the new configurations (or you can use any of the secure default zones available).

    Open Port for Specific IP Address in Firewalld

    First create an appropriate zone name (in our case, we have used mariadb-access to allow access to the MySQL database server).

    # firewall-cmd --new-zone=mariadb_access --permanent
    

    Next, reload the firewalld settings to apply the new change. If you skip this step, you may get an error when you try to use the new zone name. This time around, the new zone should appear in the list of zones as highlighted in the following screenshot.

    # firewall-cmd --reload
    # firewall-cmd --get-zones
    
    Check Firewalld Zone
    Check Firewalld Zone

    me title=

    Next, add the source IP address ( 10.24.96.5/20 ) and the port ( 3306 ) you wish to open on the local server as shown. Then reload the firewalld settings to apply the new changes.

    # firewall-cmd --zone=mariadb-access --add-source=10.24.96.5/20 --permanent
    # firewall-cmd --zone=mariadb-access --add-port=3306/tcp  --permanent
    # firewall-cmd --reload
    
    Open Port for Specific IP in Firewalld
    Open Port for Specific IP in Firewalld

    Alternatively, you can allow traffic from the entire network ( 10.24.96.0/20 ) to a service or port.

    # firewall-cmd --zone=mariadb-access --add-source=10.24.96.0/20 --permanent
    # firewall-cmd --zone=mariadb-access --add-port=3306/tcp --permanent
    # firewall-cmd --reload
    

    To confirm that the new zone has the required settings as added above, check its details with the following command.

    # firewall-cmd --zone=mariadb-access --list-all
    
    View Firewalld Zone Details
    View Firewalld Zone Details
    Remove Port and Zone from Firewalld

    You can remove the source IP address or network as shown.

    # firewall-cmd --zone=mariadb-access --remove-source=10.24.96.5/20 --permanent
    # firewall-cmd --reload
    

    To remove the port from the zone, issue the following command, and reload the firewalld settings:

    # firewall-cmd --zone=mariadb-access --remove-port=3306/tcp --permanent
    # firewall-cmd --reload
    

    To remove the zone, run the following command, and reload the firewalld settings:

    # firewall-cmd --permanent --delete-zone=mariadb_access
    # firewall-cmd --reload
    

    Last but not list, you can also use firewalld rich rules. Here is an example:

    # firewall-cmd --permanent –zone=mariadb-access --add-rich-rule='rule family="ipv4" source address="10.24.96.5/20" port protocol="tcp" port="3306" accept'
    

    Reference : Using and Configuring firewalld in the RHEL 8 documentation.

    That's it! We hope the above solutions worked for you. If yes, let us know via the feedback form below. You can as well ask questions or share general comments about this topic. Tags CentOS Tips , Fedora Tips , Firewalld Tips , RHEL Tips

    If you liked this article, then do subscribe to email alerts for Linux tutorials. If you have any questions or doubts? do ask for help in the comments section.

    [Jul 19, 2020] NetworkManager 1.26 Brings Autoconnect for Wi-Fi Profiles, firewalld zone Support - 9to5Linux

    Jul 19, 2020 | 9to5linux.com

    NetworkManager 1.26 has been released as the latest stable series of this powerful and widely used network connection manager designed for the GNOME desktop environment .

    Numerous GNU/Linux distributions ship with NetworkManager by default to allow users to manage network connections, whether they're Wi-Fi or wired connections or VPN connections.

    In NetworkManager 1.26, there's now automatic connection for Wi-Fi profiles when all previous activation attempts fail. Previously, if a Wi-Fi profile failed to autoconnect to the network, the automatism was blocked.

    Another cool new feature is a build option called firewalld-zone, which is enabled by default and lets NetworkManager install a firewalld zone for connection sharing. This also puts network interfaces that use IPv4 or IPv6 shared mode in this firewalld zone during activation.

    The new firewalld-zone option is more useful on Linux systems that use the firewalld firewall management tool with the nftables backend. However, it looks like NetworkManager continues to use iptables for enabling masquerading and open the required ports for DHCP and DNS.

    NetworkManager 1.26 also adds a MUD URL property for connection profiles (RFC 8520) and sets it for DHCP and DHCPv6 requests, support for the ethtool coalesce and ring options, support for "local" type routes beside "unicast," support for several bridge options, and adds match for device path, driver and kernel command-line for connection profiles.

    Support for OVS patch interfaces has been improved in this release, which introduces a new provider in the nm-cloud-setup component for Google Cloud Platform. This is useful to automatically detect and configure the host to receive network traffic from internal load balancers.

    Among other noteworthy changes, the syntax was extended to 'match' setting properties with '|', '&', '!' and '\', raw LLDP message is now exposed on D-Bus and the MUD usage description URL, and team connections are now allowed to work without D-Bus.

    New manual pages for the nm-settings-dbus and nm-settings-nmcli components have been introduced as well, along with support more tc qdiscs: tbf and sfq, as well as the ability for ifcfg-rh to handle 802-1x.pin properties and "802-1x.{,phase2-}ca-path" (fixes CVE-2020-10754 ).

    Last but not least, NetworkManager now marks externally managed devices and profiles on D-Bus and highlight externally managed devices in nmcli. For Ethernet connections, NetworkManager now automatically resets the original autonegotiation, duplex and speed settings when deactivating the device.

    NetworkManager 1.26 is available for download here , but it's only the sources which needs to be compiled. Therefore, I strongly recommend that you update to this new stable version from the stable software repositories of your favorite GNU/Linux distribution as it's an important component.

    [Jul 18, 2020] block all but a few ips with firewalld

    Jul 18, 2020 | serverfault.com

    Ask Question Asked 5 years, 3 months ago Active 22 days ago Viewed 42k times

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    On a linux networked machine, i would like to restrict the set of addresses on the "public" zone (firewalld concept), that are allowed to reach it. So the end result would be no other machine can access any port or protocol, except those explicitly allowed, sort of a mix of

      --add-rich-rule='rule family="ipv4" source not  address="192.168.56.120" drop'
    
      --add-rich-rule='rule family="ipv4" source not  address="192.168.56.105" drop'
    

    The problem above is that this is not a real list, it will block everything since if its one address its blocked by not being the same as the other, generating an accidental "drop all" effect, how would i "unblock" a specific non contiguous set? does source accept a list of addresses? i have not see anything in my look at the docs or google result so far.


    EDIT: I just created this:

    # firewall-cmd  --zone=encrypt --list-all
    encrypt (active)
      interfaces: eth1
      sources: 192.168.56.120
      services: ssh
      ports: 6000/tcp
      masquerade: no
      forward-ports: 
      icmp-blocks: 
      rich rules:
    

    But i can still reach port 6000 from .123 my intention was that if a source is not listed, it should not be able to reach any service or port command-line-interface fedora firewalld share improve this question follow edited Apr 6 '15 at 21:20 asked Apr 6 '15 at 20:26 mike 358 1 1 gold badge 2 2 silver badges 10 10 bronze badges add a comment 3 Answers Active Oldest Votes 26

    The rich rules aren't necessary at all.

    If you want to restrict a zone to a specific set of IPs, simply define those IPs as sources for the zone itself (and remove any interface definition that may be present, as they override source IPs).

    You probably don't want to do this to the "public" zone, though, since that's semantically meant for public facing services to be open to the world.

    Instead, try using a different zone such as "internal" for mostly trusted IP addresses to access potentially sensitive services such as sshd. (You can also create your own zones.)

    Warning: don't mistake the special "trusted" zone with the normal "internal" zone. Any sources added to the "trusted" zone will be allowed through on all ports; adding services to "trusted" zone is allowed but it doesn't make any sense to do so.

    firewall-cmd --zone=internal --add-service=ssh
    firewall-cmd --zone=internal --add-source=192.168.56.105/32
    firewall-cmd --zone=internal --add-source=192.168.56.120/32
    firewall-cmd --zone=public --remove-service=ssh
    

    The result of this will be a "internal" zone which permits access to ssh, but only from the two given IP addresses. To make it persistent, re-run each command with --permanent appended, or better, by using firewall-cmd --runtime-to-permanent . share improve this answer follow edited Jun 25 at 17:15 answered Apr 6 '15 at 20:47 Michael Hampton 202k 31 31 gold badges 395 395 silver badges 757 757 bronze badges

    show 3 more comments

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    As per firewalld.richlanguage :

    Source source [not] address="address[/mask]"

       With the source address the origin of a connection attempt can be limited to the source address. An address is either a single IP address, or a network IP address. The address has to match the rule family (IPv4/IPv6). Subnet mask is expressed in either
       dot-decimal (/x.x.x.x) or prefix (/x) notations for IPv4, and in prefix notation (/x) for IPv6 network addresses. It is possible to invert the sense of an address by adding not before address. All but the specified address will match then.
    

    Specify a netmask for the address to allow contiguous blocks.

    Other than that, you could try creating an ipset for a non-contiguous list of allowed IPs.

    For example, in /etc/firewalld/direct.xml :

    <?xml version="1.0" encoding="utf-8"?>
    <direct>
       <rule ipv="ipv4" table="filter" chain="INPUT" priority="0">-m set --match-set whitelist src -j ACCEPT</rule>
    </direct>
    

    The actual ipset has to be created separately. share improve this answer follow edited Apr 7 '15 at 6:17 answered Apr 6 '15 at 20:53 dawud 14.2k 3 3 gold badges 38 38 silver badges 59 59 bronze badges

    add a comment 0

    You can manage easily by Rich Rule.

    First Step

    firewall-cmd --permanent --set-default-zone=home
    firewall-cmd --permanent --zone=drop --change-interface=eth0
    

    Second Step - Add Rich Rule

    firewall-cmd --permanent --zone=home --add-rich-rule='rule family="ipv4" source address="192.168.78.76/32" accept'
    

    All port is accessible by 192.168.2.2 once you add rich rule and blocked every port from other source.

    If you will add any port or service by below command then it will accessible by all sources.

    firewall-cmd --zone=public --add-service=ssh
    firewall-cmd --zone=public --add-port=8080
    

    If you want to open specific port for specific Ip than below command

    firewall-cmd --permanent --zone=home --add-rich-rule='rule family="ipv4" port="8080/tcp" source address="192.168.78.76/32" accept'
    
    share improve this answer follow answered Jan 12 '17 at 16:28 Ranjeet Ranjan 129 1 1 bronze badge add a comment

    [Jul 18, 2020] 5.12. Setting and Controlling IP sets using firewalld Red Hat Enterprise Linux 7 - Red Hat Customer Portal

    Jul 18, 2020 | access.redhat.com

    5.12. SETTING AND CONTROLLING IP SETS USING FIREWALLD To see the list of IP set types supported by firewalld , enter the following command as root.

    ~]# firewall-cmd --get-ipset-types
    hash:ip hash:ip,mark hash:ip,port hash:ip,port,ip hash:ip,port,net hash:mac hash:net hash:net,iface hash:net,net hash:net,port hash:net,port,net
    
    5.12.1. Configuring IP Set Options with the Command-Line Client IP sets can be used in firewalld zones as sources and also as sources in rich rules. In Red Hat Enterprise Linux 7, the preferred method is to use the IP sets created with firewalld in a direct rule. To list the IP sets known to firewalld in the permanent environment, use the following command as root :
    ~]# firewall-cmd --permanent --get-ipsets
    
    To add a new IP set, use the following command using the permanent environment as root :
    ~]# firewall-cmd --permanent --new-ipset=test --type=hash:net
    success
    
    The previous command creates a new IP set with the name test and the hash:net type for IPv4 . To create an IP set for use with IPv6 , add the --option=family=inet6 option. To make the new setting effective in the runtime environment, reload firewalld . List the new IP set with the following command as root :
    ~]# firewall-cmd --permanent --get-ipsets
    test
    
    To get more information about the IP set, use the following command as root :
    ~]# firewall-cmd --permanent --info-ipset=test
    test
    type: hash:net
    options:
    entries:
    
    Note that the IP set does not have any entries at the moment. To add an entry to the test IP set, use the following command as root :
    ~]# firewall-cmd --permanent --ipset=test --add-entry=192.168.0.1
    success
    
    The previous command adds the IP address 192.168.0.1 to the IP set. To get the list of current entries in the IP set, use the following command as root :
    ~]# firewall-cmd --permanent --ipset=test --get-entries
    192.168.0.1
    
    Generate a file containing a list of IP addresses, for example:
    ~]# cat > iplist.txt <<EOL
    192.168.0.2
    192.168.0.3
    192.168.1.0/24
    192.168.2.254
    EOL
    
    The file with the list of IP addresses for an IP set should contain an entry per line. Lines starting with a hash, a semi-colon, or empty lines are ignored. To add the addresses from the iplist.txt file, use the following command as root :
    ~]# firewall-cmd --permanent --ipset=test --add-entries-from-file=iplist.txt
    success
    
    To see the extended entries list of the IP set, use the following command as root :
    ~]# firewall-cmd --permanent --ipset=test --get-entries
    192.168.0.1
    192.168.0.2
    192.168.0.3
    192.168.1.0/24
    192.168.2.254
    
    To remove the addresses from the IP set and to check the updated entries list, use the following commands as root :
    ~]# firewall-cmd --permanent --ipset=test --remove-entries-from-file=iplist.txt
    success
    ~]# firewall-cmd --permanent --ipset=test --get-entries 192.168.0.1
    
    You can add the IP set as a source to a zone to handle all traffic coming in from any of the addresses listed in the IP set with a zone. For example, to add the test IP set as a source to the drop zone to drop all packets coming from all entries listed in the test IP set, use the following command as root :
    ~]# firewall-cmd --permanent --zone=drop --add-source=ipset:test
    success
    
    The ipset: prefix in the source shows firewalld that the source is an IP set and not an IP address or an address range. Only the creation and removal of IP sets is limited to the permanent environment, all other IP set options can be used also in the runtime environment without the --permanent option. 5.12.2. Configuring a Custom Service for an IP Set To configure a custom service to create and load the IP set structure before firewalld starts:
    1. Using an editor running as root , create a file as follows:
      ~]# vi /etc/systemd/system/ipset_name.service
      [Unit]
      Description=ipset_name
      Before=firewalld.service
      
      [Service]
      Type=oneshot
      RemainAfterExit=yes
      ExecStart=/usr/local/bin/ipset_name.sh start
      ExecStop=/usr/local/bin/ipset_name.sh stop
      
      [Install]
      WantedBy=basic.target
      
    2. Use the IP set permanently in firewalld :
      ~]# vi /etc/firewalld/direct.xml
      <?xml version="1.0" encoding="utf-8"?>
      <direct>
              <rule ipv="ipv4" table="filter" chain="INPUT" priority="0">-m set --match-set <replaceable>ipset_name</replaceable> src -j DROP</rule>
      </direct>
      
    3. A firewalld reload is required to activate the changes:
      ~]# firewall-cmd --reload
      
      This reloads the firewall without losing state information (TCP sessions will not be terminated), but service disruption is possible during the reload.

    Warning Red Hat does not recommend using IP sets that are not managed through firewalld . To use such IP sets, a permanent direct rule is required to reference the set, and a custom service must be added to create these IP sets. This service needs to be started before firewalld starts, otherwise firewalld is not able to add the direct rules using these sets. You can add permanent direct rules with the /etc/firewalld/direct.xml file.

    [Jul 18, 2020] How to Restrict Network Access Using FirewallD

    Jul 18, 2020 | www.tecmint.com

    How to Restrict Network Access Using FirewallD Ravi Saive July 16, 2020 Categories CentOS , Fedora , Firewalls , RedHat , Security Leave a comment

    me title=

    As a Linux user, you can opt either to allow or restrict network access to some services or IP addresses using the firewalld firewall which is native to CentOS/RHEL 8 and most RHEL based distributions such as Fedora .

    The firewalld firewall uses the firewall-cmd command-line utility to configure firewall rules.

    Before we can perform any configurations, let's first enable the firewalld service using the systemctl utility as shown:

    $ sudo systemctl enable firewalls
    

    Once enabled, you can now start firewalld service by executing:

    $ sudo systemctl start firewalls
    

    You can verify the status of firewalld by running the command:

    $ sudo systemctl status firewalls
    

    me title=

    The output below confirms that the firewalld service is up and running.

    Check Firewalld Status
    Check Firewalld Status
    Configuring Rules using Firewalld

    Now that we have firewalld running, we can go straight to making some configurations. Firewalld allows you to add and block ports, blacklist, as well as whitelist IP, addresses to provide access to the server. Once done with the configurations, always ensure that you reload the firewall for the new rules to take effect.

    Adding a TCP/UDP Port

    To add a port, say port 443 for HTTPS , use the syntax below. Note that you have to specify whether the port is a TCP or UDP port after the port number:

    $ sudo firewall-cmd --add-port=22/tcp --permanent
    

    Similarly, to add a UDP port, specify the UDP option as shown:

    $ sudo firewall-cmd --add-port=53/tcp --permanent
    

    The --permanent flag ensures that the rules persist even after a reboot.

    Blocking a TCP/UDP Port

    To block a TCP port, like port 22 , run the command.

    $ sudo firewall-cmd --remove-port=22/tcp --permanent
    

    Similarly, blocking a UDP port will follow the same syntax:

    $ sudo firewall-cmd --remove-port=53/udp --permanent
    
    Allowing a Service

    Network services are defined in the /etc/services file. To allow a service such as https , execute the command:

    $ sudo firewall-cmd --add-service=https
    
    Blocking a Service

    To block a service, for instance, FTP , execute:

    $ sudo firewall-cmd --remove-service=https
    
    Whitelisting an IP address

    To allow a single IP address across the firewall, execute the command:

    $ sudo firewall-cmd --permanent --add-source=192.168.2.50
    

    You can also allow a range of IPs or an entire subnet using a CIDR (Classless Inter-Domain Routing) notation. For example to allow an entire subnet in the 255.255.255.0 subnet, execute.

    $ sudo firewall-cmd --permanent --add-source=192.168.2.0/24
    
    Removing a Whitelisted IP address

    If you wish to remove a whitelisted IP on the firewall, use the --remove-source flag as shown:

    $ sudo firewall-cmd --permanent --remove-source=192.168.2.50
    

    For the entire subnet, run:

    $ sudo firewall-cmd --permanent --remove-source=192.168.2.50/24
    
    Blocking an IP address

    So far, we have seen how you can add and remove ports and services as well as whitelisting and removing whitelisted IPs. To block an IP address, ' rich rules ' are used for this purpose.

    For example to block the IP 192.168.2.50 run the command:

    $ sudo firewall-cmd --permanent --add-rich-rule="rule family='ipv4' source address='192.168.2.50' reject"
    

    To block the entire subnet, run:

    $ sudo firewall-cmd --permanent --add-rich-rule="rule family='ipv4' source address='192.168.2.0/24' reject"
    
    Saving Firewall Rules

    If you have made any changes to the firewall rules, you need to run the command below for the changes to be applied immediately:

    $ sudo firewall-cmd --reload
    
    Viewing the Firewall Rules

    To have to peek at all the rules in the firewall, execute the command:

    $ sudo firewall-cmd --list-all
    
    View Firewalld Rules

    [Jul 18, 2020] Messaging apps are getting more use, and it's putting companies at risk

    Jul 18, 2020 | www.techrepublic.com

  • Tech company offers free online cybersecurity training courses
  • Upgrade your personal security with a password manager or security key
  • Kubernetes security guide (free PDF)
  • One particular concept found in firewalld is that of zones. Zones are predefined sets of rules that specify what traffic should be allowed, based on trust levels for network connections. For example, you can have zones for home, public, trusted, etc. Zones work on a one-to-many relation, so a connection can only be part of a single zone, but a zone can be used for many network connections. Different network interfaces and sources can be assigned to specific zones.

    SEE: Information security policy (Tech Pro Research)

    There are a number of zones provided by firewalld:

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    You can easily assign an interface to one of the above zones, but there is one thing to be taken care of first .

    Installing firewalld

    You might be surprised to find out that firewalld isn't installed by default. To fix that issue, open a terminal window and issue the following command:

    sudo yum install firewalld
    

    Once that installation completes, you'll need to start and enable firewalld with the commands:

    sudo systemctl start firewalld
    sudo systemctl enable firewalld
    

    Viewing and changing the zones

    The first thing you should do is view the default zone. Issue the command:

    sudo firewall-cmd --get-default-zone
    

    You will probably see that the default zone is set to public. If you want more information about that zone, issue the command:

    sudo firewall-cmd --zone=public --list-all
    

    You should see all the pertinent details about the public zone ( Figure A ).

    Figure A

    Figure A

    Information about our default zone.


    Let's change the default zone. Say, for instance, you want to change the zone to work. Let's first find out what zones are being used by our network interface(s). For that, issue the command:

    sudo firewall-cmd --get-active-zones
    

    You should see something like that found in Figure B .

    [Jul 17, 2020] How To Set Up a Firewall Using FirewallD on CentOS 7 by Justin Ellingwood

    Notable quotes:
    "... NOTE: This is the zone for which set of allowed IP should be defined --NNB ..."
    Jun 18, 2015 | www.digitalocean.com

    Firewalld is a firewall management solution available for many Linux distributions which acts as a frontend for the iptables packet filtering system provided by the Linux kernel. In this guide, we will cover how to set up a firewall for your server and show you the basics of managing the firewall with the firewall-cmd administrative tool (if you'd rather use iptables with CentOS, follow this guide ).

    Note: There is a chance that you may be working with a newer version of firewalld than was available at the time of this writing, or that your server was set up slightly differently than the example server used throughout this guide. Thus, the behavior of some of the commands explained in this guide may vary depending on your specific configuration.

    Basic Concepts in Firewalld

    Before we begin talking about how to actually use the firewall-cmd utility to manage your firewall configuration, we should get familiar with a few basic concepts that the tool introduces.

    Zones

    The firewalld daemon manages groups of rules using entities called "zones". Zones are basically sets of rules dictating what traffic should be allowed depending on the level of trust you have in the networks your computer is connected to. Network interfaces are assigned a zone to dictate the behavior that the firewall should allow.

    For computers that might move between networks frequently (like laptops), this kind of flexibility provides a good method of changing your rules depending on your environment. You may have strict rules in place prohibiting most traffic when operating on a public WiFi network, while allowing more relaxed restrictions when connected to your home network. For a server, these zones are not as immediately important because the network environment rarely, if ever, changes.

    Regardless of how dynamic your network environment may be, it is still useful to be familiar with the general idea behind each of the predefined zones for firewalld . In order from least trusted to most trusted , the predefined zones within firewalld are:

    To use the firewall, we can create rules and alter the properties of our zones and then assign our network interfaces to whichever zones are most appropriate.

    Rule Permanence

    In firewalld, rules can be designated as either permanent or immediate. If a rule is added or modified, by default, the behavior of the currently running firewall is modified. At the next boot, the old rules will be reverted.

    Most firewall-cmd operations can take the --permanent flag to indicate that the non-ephemeral firewall should be targeted. This will affect the rule set that is reloaded upon boot. This separation means that you can test rules in your active firewall instance and then reload if there are problems. You can also use the --permanent flag to build out an entire set of rules over time that will all be applied at once when the reload command is issued.

    Install and Enable Your Firewall to Start at Boot

    firewalld is installed by default on some Linux distributions, including many images of CentOS 7. However, it may be necessary for you to install firewalld yourself:

    After you install firewalld , you can enable the service and reboot your server. Keep in mind that enabling firewalld will cause the service to start up at boot. It is best practice to create your firewall rules and take the opportunity to test them before configuring this behavior in order to avoid potential issues.

    When the server restarts, your firewall should be brought up, your network interfaces should be put into the zones you configured (or fall back to the configured default zone), and any rules associated with the zone(s) will be applied to the associated interfaces.

    We can verify that the service is running and reachable by typing:

    output running

    This indicates that our firewall is up and running with the default configuration.

    Getting Familiar with the Current Firewall Rules

    Before we begin to make modifications, we should familiarize ourselves with the default environment and rules provided by the daemon.

    Exploring the Defaults

    We can see which zone is currently selected as the default by typing:

    output public

    Since we haven't given firewalld any commands to deviate from the default zone, and none of our interfaces are configured to bind to another zone, that zone will also be the only "active" zone (the zone that is controlling the traffic for our interfaces). We can verify that by typing:

    output public interfaces: eth0 eth1

    Here, we can see that our example server has two network interfaces being controlled by the firewall ( eth0 and eth1 ). They are both currently being managed according to the rules defined for the public zone.

    How do we know what rules are associated with the public zone though? We can print out the default zone's configuration by typing:

    output public (default, active) target: default icmp-block-inversion: no interfaces: eth0 eth1 sources: services: ssh dhcpv6-client ports: protocols: masquerade: no forward-ports: source-ports: icmp-blocks: rich rules:

    We can tell from the output that this zone is both the default and active and that the eth0 and eth1 interfaces are associated with this zone (we already knew all of this from our previous inquiries). However, we can also see that this zone allows for the normal operations associated with a DHCP client (for IP address assignment) and SSH (for remote administration).

    Exploring Alternative Zones

    Now we have a good idea about the configuration for the default and active zone. We can find out information about other zones as well.

    To get a list of the available zones, type:

    output block dmz drop external home internal public trusted work

    We can see the specific configuration associated with a zone by including the --zone= parameter in our --list-all command:

    output home interfaces: sources: services: dhcpv6-client ipp-client mdns samba-client ssh ports: masquerade: no forward-ports: icmp-blocks: rich rules:

    You can output all of the zone definitions by using the --list-all-zones option. You will probably want to pipe the output into a pager for easier viewing:

    Selecting Zones for your Interfaces

    Unless you have configured your network interfaces otherwise, each interface will be put in the default zone when the firewall is booted.

    Changing the Zone of an Interface

    You can transition an interface between zones during a session by using the --zone= parameter in combination with the --change-interface= parameter. As with all commands that modify the firewall, you will need to use sudo .

    For instance, we can transition our eth0 interface to the "home" zone by typing this:

    output success Note Whenever you are transitioning an interface to a new zone, be aware that you are probably modifying the services that will be operational. For instance, here we are moving to the "home" zone, which has SSH available. This means that our connection shouldn't drop. Some other zones do not have SSH enabled by default and if your connection is dropped while using one of these zones, you could find yourself unable to log back in.

    We can verify that this was successful by asking for the active zones again:

    output home interfaces: eth0 public interfaces: eth1 Adjusting the Default Zone

    If all of your interfaces can best be handled by a single zone, it's probably easier to just select the best default zone and then use that for your configuration.

    You can change the default zone with the --set-default-zone= parameter. This will immediately change any interface that had fallen back on the default to the new zone:

    output success Setting Rules for your Applications

    The basic way of defining firewall exceptions for the services you wish to make available is easy. We'll run through the basic idea here.

    Adding a Service to your Zones

    The easiest method is to add the services or ports you need to the zones you are using. Again, you can get a list of the available services with the --get-services option:

    output RH-Satellite-6 amanda-client amanda-k5-client bacula bacula-client bitcoin bitcoin-rpc bitcoin-testnet bitcoin-testnet-rpc ceph ceph-mon cfengine condor-collector ctdb dhcp dhcpv6 dhcpv6-client dns docker-registry dropbox-lansync elasticsearch freeipa-ldap freeipa-ldaps freeipa-replication freeipa-trust ftp ganglia-client ganglia-master high-availability http https imap imaps ipp ipp-client ipsec iscsi-target kadmin kerberos kibana klogin kpasswd kshell ldap ldaps libvirt libvirt-tls managesieve mdns mosh mountd ms-wbt mssql mysql nfs nrpe ntp openvpn ovirt-imageio ovirt-storageconsole ovirt-vmconsole pmcd pmproxy pmwebapi pmwebapis pop3 pop3s postgresql privoxy proxy-dhcp ptp pulseaudio puppetmaster quassel radius rpc-bind rsh rsyncd samba samba-client sane sip sips smtp smtp-submission smtps snmp snmptrap spideroak-lansync squid ssh synergy syslog syslog-tls telnet tftp tftp-client tinc tor-socks transmission-client vdsm vnc-server wbem-https xmpp-bosh xmpp-client xmpp-local xmpp-server Note

    You can get more details about each of these services by looking at their associated .xml file within the /usr/lib/firewalld/services directory. For instance, the SSH service is defined like this:

    /usr/lib/firewalld/services/ssh.xml
    <?xml version="1.0" encoding="utf-8"?>
    <service>
      <short>SSH</short>
      <description>Secure Shell (SSH) is a protocol for logging into and executing commands on remote machines. It provides secure encrypted communications. If you plan on accessing your machine remotely via SSH over a firewalled interface, enable this option. You need the openssh-server package installed for this option to be useful.</description>
      <port protocol="tcp" port="22"/>
    </service>
    


    You can enable a service for a zone using the --add-service= parameter. The operation will target the default zone or whatever zone is specified by the --zone= parameter. By default, this will only adjust the current firewall session. You can adjust the permanent firewall configuration by including the --permanent flag.

    For instance, if we are running a web server serving conventional HTTP traffic, we can allow this traffic for interfaces in our "public" zone for this session by typing:

    You can leave out the --zone= if you wish to modify the default zone. We can verify the operation was successful by using the --list-all or --list-services operations:

    output dhcpv6-client http ssh

    Once you have tested that everything is working as it should, you will probably want to modify the permanent firewall rules so that your service will still be available after a reboot. We can make our "public" zone change permanent by typing:

    output success

    You can verify that this was successful by adding the --permanent flag to the --list-services operation. You need to use sudo for any --permanent operations:

    output dhcpv6-client http ssh

    Your "public" zone will now allow HTTP web traffic on port 80. If your web server is configured to use SSL/TLS, you'll also want to add the https service. We can add that to the current session and the permanent rule-set by typing:

    What If No Appropriate Service Is Available?

    The firewall services that are included with the firewalld installation represent many of the most common requirements for applications that you may wish to allow access to. However, there will likely be scenarios where these services do not fit your requirements.

    In this situation, you have two options.

    Opening a Port for your Zones

    The easiest way to add support for your specific application is to open up the ports that it uses in the appropriate zone(s). This is as easy as specifying the port or port range, and the associated protocol for the ports you need to open.

    For instance, if our application runs on port 5000 and uses TCP, we could add this to the "public" zone for this session using the --add-port= parameter. Protocols can be either tcp or udp :

    output success

    We can verify that this was successful using the --list-ports operation:

    output 5000/tcp

    It is also possible to specify a sequential range of ports by separating the beginning and ending port in the range with a dash. For instance, if our application uses UDP ports 4990 to 4999, we could open these up on "public" by typing:

    After testing, we would likely want to add these to the permanent firewall. You can do that by typing:

    output success success 5000/tcp 4990-4999/udp
    Defining a Service

    Opening ports for your zones is easy, but it can be difficult to keep track of what each one is for. If you ever decommission a service on your server, you may have a hard time remembering which ports that have been opened are still required. To avoid this situation, it is possible to define a service.

    Services are simply collections of ports with an associated name and description. Using services is easier to administer than ports, but requires a bit of upfront work. The easiest way to start is to copy an existing script (found in /usr/lib/firewalld/services ) to the /etc/firewalld/services directory where the firewall looks for non-standard definitions.

    For instance, we could copy the SSH service definition to use for our "example" service definition like this. The filename minus the .xml suffix will dictate the name of the service within the firewall services list:

    Now, you can adjust the definition found in the file you copied:

    sudo vi /etc/firewalld/services/example.xml
    

    To start, the file will contain the SSH definition that you copied:

    /etc/firewalld/services/example.xml
    <?xml version="1.0" encoding="utf-8"?>
    <service>
      <short>SSH</short>
      <description>Secure Shell (SSH) is a protocol for logging into and executing commands on remote machines. It provides secure encrypted communications. If you plan on accessing your machine remotely via SSH over a firewalled interface, enable this option. You need the openssh-server package installed for this option to be useful.</description>
      <port protocol="tcp" port="22"/>
    </service>
    

    The majority of this definition is actually metadata. You will want to change the short name for the service within the <short> tags. This is a human-readable name for your service. You should also add a description so that you have more information if you ever need to audit the service. The only configuration you need to make that actually affects the functionality of the service will likely be the port definition where you identify the port number and protocol you wish to open. This can be specified multiple times.

    For our "example" service, imagine that we need to open up port 7777 for TCP and 8888 for UDP. By entering INSERT mode by pressing i , we can modify the existing definition with something like this:

    /etc/firewalld/services/example.xml
    <?xml version="1.0" encoding="utf-8"?>
    <service>
      <short>Example Service</short>
      <description>This is just an example service.  It probably shouldn't be used on a real system.</description>
      <port protocol="tcp" port="7777"/>
      <port protocol="udp" port="8888"/>
    </service>
    

    Press ESC , then enter :x to save and close the file.

    Reload your firewall to get access to your new service:

    You can see that it is now among the list of available services:

    output RH-Satellite-6 amanda-client amanda-k5-client bacula bacula-client bitcoin bitcoin-rpc bitcoin-testnet bitcoin-testnet-rpc ceph ceph-mon cfengine condor-collector ctdb dhcp dhcpv6 dhcpv6-client dns docker-registry dropbox-lansync elasticsearch example freeipa-ldap freeipa-ldaps freeipa-replication freeipa-trust ftp ganglia-client ganglia-master high-availability http https imap imaps ipp ipp-client ipsec iscsi-target kadmin kerberos kibana klogin kpasswd kshell ldap ldaps libvirt libvirt-tls managesieve mdns mosh mountd ms-wbt mssql mysql nfs nrpe ntp openvpn ovirt-imageio ovirt-storageconsole ovirt-vmconsole pmcd pmproxy pmwebapi pmwebapis pop3 pop3s postgresql privoxy proxy-dhcp ptp pulseaudio puppetmaster quassel radius rpc-bind rsh rsyncd samba samba-client sane sip sips smtp smtp-submission smtps snmp snmptrap spideroak-lansync squid ssh synergy syslog syslog-tls telnet tftp tftp-client tinc tor-socks transmission-client vdsm vnc-server wbem-https xmpp-bosh xmpp-client xmpp-local xmpp-server

    You can now use this service in your zones as you normally would.

    Creating Your Own Zones

    While the predefined zones will probably be more than enough for most users, it can be helpful to define your own zones that are more descriptive of their function.

    For instance, you might want to create a zone for your web server, called "publicweb". However, you might want to have another zone configured for the DNS service you provide on your private network. You might want a zone called "privateDNS" for that.

    When adding a zone, you must add it to the permanent firewall configuration. You can then reload to bring the configuration into your running session. For instance, we could create the two zones we discussed above by typing:

    You can verify that these are present in your permanent configuration by typing:

    output block dmz drop external home internal privateDNS public publicweb trusted work

    As stated before, these won't be available in the current instance of the firewall yet:

    output block dmz drop external home internal public trusted work

    Reload the firewall to bring these new zones into the active configuration:

    output block dmz drop external home internal privateDNS public publicweb trusted work

    Now, you can begin assigning the appropriate services and ports to your zones. It's usually a good idea to adjust the active instance and then transfer those changes to the permanent configuration after testing. For instance, for the "publicweb" zone, you might want to add the SSH, HTTP, and HTTPS services:

    output publicweb target: default icmp-block-inversion: no interfaces: sources: services: ssh http https ports: protocols: masquerade: no forward-ports: source-ports: icmp-blocks: rich rules:

    Likewise, we can add the DNS service to our "privateDNS" zone:

    output privateDNS interfaces: sources: services: dns ports: masquerade: no forward-ports: icmp-blocks: rich rules:

    We could then change our interfaces over to these new zones to test them out:

    At this point, you have the opportunity to test your configuration. If these values work for you, you will want to add the same rules to the permanent configuration. You can do that by re-applying the rules with the --permanent flag:

    After permanently applying these your rules, you can restart your network and reload your firewall service:

    Validate that the correct zones were assigned:

    output privateDNS interfaces: eth1 publicweb interfaces: eth0

    And validate that the appropriate services are available for both of the zones:

    output http https ssh output dns

    You have successfully set up your own zones! If you want to make one of these zones the default for other interfaces, remember to configure that behavior with the --set-default-zone= parameter:

    sudo firewall-cmd --set-default-zone=publicweb
    
    Conclusion

    You should now have a fairly good understanding of how to administer the firewalld service on your CentOS system for day-to-day use.

    The firewalld service allows you to configure maintainable rules and rule-sets that take into consideration your network environment. It allows you to seamlessly transition between different firewall policies through the use of zones and gives administrators the ability to abstract the port management into more friendly service definitions. Acquiring a working knowledge of this system will allow you to take advantage of the flexibility and power that this tool provides.

    How do I get firewalld to restrict access to all except specified IP addresses?

    I would appreciate some assistance with configuring firewalld please. Here's a bit of background. All I want to do is prevent all access- except whitelisted IP addresses to a web application running on https.

    I have done much googling. learnt a number of things but none has worked yet. Here's what I have done:

    1. I can tell firewalld is running

      # systemctl status firewalld
      
      firewalld.service - firewalld - dynamic     firewall daemon    Loaded: loaded
      (/usr/lib/systemd/system/firewalld.service; enabled)    Active: active
      (running)
      

    also with

        # firewall-cmd --state
        running
    
    1. I have the default zones

      # firewall-cmd --get-zones
      block dmz drop external home internal public trusted work
      
    2. My active zones include:

      # firewall-cmd --get-active-zones
      public
      sources: 192.72.0.193 192.72.0.0/22 94.27.256.190
      
    3. My default zone is public:

      # firewall-cmd --get-default-zone
      public
      
    4. The details of public are:

      public (default)   
      interfaces:   
      sources: 192.72.0.193 192.72.0.0/22 94.27.256.190   
      services: http https ssh   
      ports:   
      masquerade: no   
      forward-ports:   
      icmp-blocks:   
      rich rules:
      

    My understanding is that the configuration for public zone above will restrict only grant to requests from any of the specified IP addresses. However, when I try accessing https://www.example.com from an IP outside the listed, it allows it. iptables redhat centos7 firewalld share improve this question follow edited Apr 16 '15 at 22:32

    dawud 14.2k 3 3 gold badges 38 38 silver badges 59 59 bronze badges asked Apr 16 '15 at 11:36

    pi. 219 3 3 silver badges 8 8 bronze badges

    add a comment

    1 Answer Active Oldest Votes 2

    one option is to remove the service: https from the zone

    firewall-cmd --zone=public --remove-service=https
    

    and then use what is known as rich rules to specify what sources [IP addresses] may access what service [such as http and https] like so:

    firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="x.x.x.0/24" service name="https" log prefix="https" level="info" accept'
    

    might need to reload though

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