Linux Routing Configuration

External

• https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Networking_Guide/sec-Using_the_Command_Line_Interface.html#sec-Configuring_Static_Routes_in_ifcfg_files

Internal

• Routing

Listing Routes

ip route

Adding a Static Route via a Specific Interface

TODO

Route changes operated with ip are not saved. See Routing configuration that survives reboot.

ip route add ...

Adding Multicast Routing to a Specific Network Interface

ip route add 224.0.0.0/4 dev <device-name>

More details about ip can be found here

ip

The equivalent "route" command is:

route add 224.0.0.0 netmask 240.0.0.0 dev <device-name>

More information:

http://lartc.org/howto/lartc.multicast.html

Deleting a Route

TODO

Route changes operated with ip are not saved. See Routing configuration that survives reboot.

ip route delete  ...

Routing Configuration that Survives Reboot

Add the static routing configuration to /etc/sysconfig/network-scripts/route-<device-name>:

...
# default multicast route
224.0.0.0/4 via 172.20.1.12

where "172.20.1.12" is the IP address of the interface we want to route the multicast traffic over. It is sufficient to add static routing configuration only to the file route-* corresponding to the interface that will service the route.

After reboot, we'll get this:

[eap@app01 ~]$ ip route
...
224.0.0.0/4 via 172.20.1.12 dev eth1

Default Route

An interface is designate as serving the default route if it contains

DEFROUTE=yes

in its ifcfg-* configuration file.