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 +====== Static routes ======
  
 +Static routing is the term used to refer to the manual method used to set up routing. An administrator enters routes into the router using configuration commands. This method has the advantage of being predictable,​ and simple to set up. It is easy to manage in small networks but does not scale well.
 +
 +
 +Advantages of Static Routes
 +
 +    * Easy to configure
 +
 +    * No routing protocol overhead
 +
 +Disadvantages of Static Routes
 +
 +    * Network changes require manual reconfiguration
 +
 +    * Network outages cannot be automatically routed around
 +
 +    * Does not scale well in large networks.
 +
 +Add a Static route using “route” command
 +
 +    route add [-net|-host] <​IP/​Net>​ netmask <​Mask>​ gw <Gateway IP> dev <​Int>​X
 +
 +Example
 +
 +    route add -net 10.10.10.0 netmask 255.255.255.0 gw 192.168.1.1 dev eth0
 +    route add -host 10.10.1.1 netmask 255.255.255.0 gw 192.168.1.1 dev eth0
 +
 +This adds the route immediatly to the Kernel IP routing table. To confirm the route has been successfully,​ simply type the “route” command with no arguements:
 +
 +<​code>​
 +route
 +
 +Kernel IP routing table
 +Destination Gateway Genmask Flags Metric Ref Use Iface
 +192.168.1.254 * 255.255.255.0 U 0 0 0 eth0
 +localnet * 255.255.255.0 U 0 0 0 eth0
 +10.10.10.0 * 255.255.255.0 U 0 0 0 eth0
 +10.10.1.1 * 255.255.255.0 U 0 0 0 eth0
 +default 192.168.1.1 0.0.0.0 UG 0 0 0 eth0
 +</​code>​
 +
 +Use 
 +
 +   ​netstat -rn
 +
 +to print the Kernel IP Routing table.
 +
 +===== Ubuntu/​Debian =====
 +
 +
 +To keep the Static Route persistent or you want to add the route entries to the network script files (not using the route command) then all you need to do is to edit the file
 +
 +    /​etc/​network/​interfaces
 +
 +and the static routes in the following format:
 +
 +    up route add [-net|-host] <​host/​net>/<​mask>​ gw <​host/​IP>​ dev <​Interface>​
 +
 +Example
 +
 +    up route add -net 172.20.11.0/​16 gw 172.20.10.254 dev eth1
 +
 +And the file will like the following
 +
 +    sudo cat /​etc/​network/​interfaces
 +
 +The output should show something like this
 +
 +    sudo cat /​etc/​network/​interfaces
 +
 +The output should show something like this
 +
 +<​file>​
 +# This file describes the network interfaces available on your system
 +# and how to activate them. For more information,​ see interfaces(5).
 +
 +# The loopback network interface
 +auto lo
 +iface lo inet loopback
 +
 +# The primary network interface
 +auto eth0 eth1
 +
 +iface eth0 inet static
 +address 192.168.1.2
 +netmask 255.255.255.0
 +network 192.168.1.0
 +broadcast 192.168.1.255
 +gateway 192.168.1.254
 +# dns-* options are implemented by the resolvconf package, if installed
 +
 +iface eth1 inet static
 +address 172.20.10.1
 +netmask 255.255.255.0
 +broadcast 172.20.10.255
 +gateway 172.20.10.254
 +
 +# static route
 +up route add -net 172.20.11.0/​16 gw 172.20.10.254 dev eth1
 +</​file>​
 +
 +The above has 2 Ethernet interfaces and the static route is added to the interface eth1.
 +
 +For the change to /​etc/​network/​interface to take effect. please restart the “networking” service as follows:
 +
 +    sudo /​etc/​init.d/​networking restart
 +
 +NOTE: If you added the route already using the “route” then there is no need to restart the networking service because, the next time server is restarted this takes effect.
 +
 +===== RedHat/​Fedora =====
 +To make persistent routes in RedHat/​Fedora systems make the file "/​etc/​sysconfig/​network-scripts/​route-eth0":​
 +
 +<​file>​
 +#
 +# File /​etc/​sysconfig/​network-scripts/​route-eth0
 +#
 +10.0.0.0/8 via 192.168.1.254
 +</​file>​
 +
 +The file name is important, route-eth0 is routes being set up when eth0 goes up.
 +
 +
 +----
 +
 +Source: http://​www.ubuntugeek.com/​howto-add-permanent-static-routes-in-ubuntu.html
howtos/adding_permanent_static_routes.txt · Last modified: d/m/Y H:i (external edit)