Softpanorama

Home Switchboard Unix Administration Red Hat TCP/IP Networks Neoliberalism Toxic Managers
May the source be with you, but remember the KISS principle ;-)
Skepticism and critical thinking is not panacea, but can help to understand the world better

Setting a Default Gateway in RHEL6

News Routing Recommended Links Static Routing Typical Operations Making routing entries permanent
ip command Linux ifconfig netstat Static Routing Default Route Suse static routes table
Policy Routing Suse network configuration Redhat Network Configuration     RIP Daemon
martian source   Horror Stories Unix History Humor Etc

This can be tricky business. Haste make waist and here is very true: if you mess with specifying parameters in RHEL config file you can end with the situation troubleshooting of which can last several hours.

Some errors like specifying network that does not contain the default router can result in strange and difficult to troubleshoot behavior: If you restart networking (for example using the command service network restart) or reboot the box you lose your default router. At the same time the command

route add default gw 10.10.10.1 

will work OK.

Default gate way can be specified per interface or like global setting

Global setting specification should be put into /etc/sysconfig/network file

NETWORKING=yes
NETWORKING_IPV6=no
HOSTNAME=box2.mytown.mycompany.com
GATEWAY=10.194.176.1

After change you need to restart networking service :

/etc/init.d/networking restart
Interface  eth0 file /etc/sysconfig/network-scripts/ifcfg-eth0 in RHEL 5.8 looks like
# Broadcom Corporation NetXtreme II BCM5709 Gigabit Ethernet
DEVICE=eth0
BOOTPROTO=static
BROADCAST=10.194.191.255
HWADDR=E8:39:35:B8:28:10
IPADDR=10.194.181.231
NETMASK=255.255.240.0
NETWORK=10.194.176.0
ONBOOT=yes

Top updates

Bulletin Latest Past week Past month
Google Search


NEWS CONTENTS

Old News ;-)

Lost default Gateways after reboot

Tarn

Lost default Gateways after reboot
I have two clustered ftp servers running RH Enterprise but have an odd problem, after rebooting there are no default gateways when I run ip route.
Both servers have two interface cards on two separate LANs so I have to manually add the default gw's before I can access them from another site.

Does anyone have any idea what is causing this?

Many thanks

cannonac

Have you got any files in the /etc/sysconfig/network-scripts directory which are similar to this: ifcfg-ethx where x is the ethernet prot number?

This is an extract from one of our files:

DEVICE=eth1
HWADDR=xx: xx: xx: xx: xx
ONBOOT=yes
TYPE=Ethernet
BOOTPROTO=static
NETMASK=255.255.252.0
IPADDR=10.192.x.x
USERCTL=no
GATEWAY=10.192.x.254
IPV6INIT=no

This gateway is hard coded into the configuration file for eth1 (I know it can get overwritten, but having a copy handy may help)

That's all I can think of for the moment. If I come up with anything else, I'll let you know.

Oh, are you running with static of dynamic IPs? Is DHCP running and trying to get the network info from a DHCP server on the network?

Andy


Recommended Links

Top Visited

Bulletin Latest Past week Past month
Google Search



...



Etc

The Last but not Least Technology is dominated by two types of people: those who understand what they do not manage and those who manage what they do not understand ~Archibald Putt. Ph.D


Copyright 1996-2018 by Dr. Nikolai Bezroukov. www.softpanorama.org was initially created as a service to the (now defunct) UN Sustainable Development Networking Programme (SDNP) in the author free time and without any remuneration. This document is an industrial compilation designed and created exclusively for educational use and is distributed under the Softpanorama Content License. Original materials copyright belong to respective owners. Quotes are made for educational purposes only in compliance with the fair use doctrine.

FAIR USE NOTICE This site contains copyrighted material the use of which has not always been specifically authorized by the copyright owner. We are making such material available to advance understanding of computer science, IT technology, economic, scientific, and social issues. We believe this constitutes a 'fair use' of any such copyrighted material as provided by section 107 of the US Copyright Law according to which such material can be distributed without profit exclusively for research and educational purposes.

This is a Spartan WHYFF (We Help You For Free) site written by people for whom English is not a native language. Grammar and spelling errors should be expected. The site contain some broken links as it develops like a living tree...

You can use PayPal to make a contribution, supporting development of this site and speed up access. In case softpanorama.org is down you can use the at softpanorama.info

Disclaimer:

The statements, views and opinions presented on this web page are those of the author (or referenced source) and are not endorsed by, nor do they necessarily reflect, the opinions of the author present and former employers, SDNP or any other organization the author may be associated with. We do not warrant the correctness of the information provided or its fitness for any purpose.

The site uses AdSense so you need to be aware of Google privacy policy. You you do not want to be tracked by Google please disable Javascript for this site. This site is perfectly usable without Javascript.

Last modified: July 28, 2019