Default Router, Network Mask, and Broadcast Address

Most devices attached to the campus network learn the IP address of their default IP router (a.k.a "gateway") via DHCP or BootP. Some do so by listening to RIPv1 routing announcements. If your device cannot use any of those methods, you may use this table to learn the IP address of the appropriate default IP router (a.k.a "gateway"), so you may manually configure your device with this information.

Most devices attached to the campus network learn the IP network mask (a.k.a. "netmask") via DHCP or BootP. If your device cannot use either of those methods, you may use this table to learn the appropriate network mask, so you may manually configure your device with this information.

Some devices attached to the campus network learn the IP broadcast address via DHCP or BootP. If your device cannot use either of those methods, you may use this table to learn the the appropriate IP broadcast address, so you may manually configure your device with this inforamtion.

In the first column, locate the range of IP addresses that include the IP address already assigned to your computer. In the second column, you can read off the appropriate default router IP address. In the third column you can read off the network mask, and the fourth column shows the broadcast address.

For example: if your IP address is 128.112.177.234, then the the IP address of the default IP router is 128.112.176.1, your network mask is 255.255.252.0, and the broadcast address is 128.112.176.0.

1. The preferred (recommended) address is 128.112.144.1. However, the older address 128.112.144.248 will also work and continues to be supported. (Don't use both; they are actually both the same device.)

    

2. There is no default IP router for this network; it is isolated, not routed to any other network.

    

3. The preferred (recommended) address is 128.112.200.1. However, the older address 128.112.204.1 will also work and continues to be supported. (Don't use both; they are actually the same device.)

    

4. The older value 255.255.252.0 continues to work, but will not provide optimal performance. All devices that were manually configured to use the old value should be reconfigured to use the new value.

    

5. The preferred (recommended) address is 128.112.40.1. However, the older address 128.112.44.1 will also work and continues to be supported. (Don't use both; they are actually the same device.)

Old News ;-)

From the computer of: qmchenry (203 recipes)

created: 2003-07-11 00:00:00 last updated: 2003-09-29 13:31:07

Directions

Step 1: edit /etc/defaultrouter

Using the editor of your choice, edit the file /etc/defaultrouter -- the only line in the file should be the default route of the system, for example: 192.168.1.1. This change will not take effect until the system is rebooted.

Step 2: Delete the current default route

To make the route change take effect immediately, you must first delete the default route. If the current default route is 192.168.254.1, then the command would be:

route delete default 192.168.254.1

Step 3: Assign the current default route

To implement the new default route without rebooting the system, use the following command substituting your default route for 192.168.1.1:

route add default 192.168.1.1