STATIC

STATIC is a daemon that handles the installation and deletion of static routes.

Static Route Commands

Static routing is a very fundamental feature of routing technology. It defines a static prefix and gateway, with several possible forms.

ip route NETWORK GATEWAY [DISTANCE] [table TABLENO] [nexthop-vrf VRFNAME] [vrf VRFNAME]
ip route NETWORK IFNAME [DISTANCE] [table TABLENO] [nexthop-vrf VRFNAME] [vrf VRFNAME]
ip route NETWORK (Null0|blackhole|reject) [DISTANCE] [table TABLENO] [nexthop-vrf VRFNAME] [vrf VRFNAME]
ipv6 route NETWORK [from SRCPREFIX] GATEWAY [DISTANCE] [table TABLENO] [nexthop-vrf VRFNAME] [vrf VRFNAME]
ipv6 route NETWORK [from SRCPREFIX] IFNAME [DISTANCE] [table TABLENO] [nexthop-vrf VRFNAME] [vrf VRFNAME]
ipv6 route NETWORK [from SRCPREFIX] (Null0|blackhole|reject) [DISTANCE] [table TABLENO] [nexthop-vrf VRFNAME] [vrf VRFNAME]

Multiple nexthop static route

To create multiple nexthops to the same NETWORK (also known as a multipath route), just reenter the same network statement with different nexthop information.

ip route 10.0.0.1/32 10.0.0.2
ip route 10.0.0.1/32 10.0.0.3
ip route 10.0.0.1/32 eth0

If there is no route to 10.0.0.2 and 10.0.0.3, and interface eth0 is reachable, then the last route is installed into the kernel.

If zebra has been compiled with multipath support, and both 10.0.0.2 and 10.0.0.3 are reachable, zebra will install a multipath route via both nexthops, if the platform supports this.

router> show ip route
S>  10.0.0.1/32 [1/0] via 10.0.0.2 inactive
    via 10.0.0.3 inactive
  *       is directly connected, eth0

ip route 10.0.0.0/8 10.0.0.2
ip route 10.0.0.0/8 10.0.0.3
ip route 10.0.0.0/8 null0 255

This will install a multipath route via the specified next-hops if they are reachable, as well as a high-distance blackhole route, which can be useful to prevent traffic destined for a prefix to match less-specific routes (e.g. default) should the specified gateways not be reachable. E.g.:

router> show ip route 10.0.0.0/8
Routing entry for 10.0.0.0/8
  Known via "static", distance 1, metric 0
    10.0.0.2 inactive
    10.0.0.3 inactive

Routing entry for 10.0.0.0/8
  Known via "static", distance 255, metric 0
    directly connected, Null0

Also, if the user wants to configure a static route for a specific VRF, then a specific VRF configuration mode is available. After entering into that mode with vrf VRF the user can enter the same route command as before, but this time, the route command will apply to the VRF.

# case with VRF
configure
vrf r1-cust1
 ip route 10.0.0.0/24 10.0.0.2
exit-vrf