Advertising Static Routes

[BlueyVIII]

Hello,

Our EIGRP network will soon be connected to a 3rd party network which we have no control over. The 3rd Party are refusing to take part in any dynamic routing but have hundreds of non-contigous subnets which we must route using static routes. To compound things further we'll have two routes into the 3rd party network (a primary and a secondary) for resilience. Ideally the connectivity should switch between the two links without any manual reconfiguation.

Is there a way that we can configure a router (in this case a 6509) to monitor a the 3rd party network (subnet or interface) and advertise a route into our network as long as that interface or subnet is up? If our network looses contact with the 3rd party network or interface then our 6509 stops advertising that route into the network.

Hope that makes sense?

[Mahesh Gohil]

Hello,

If I have understood correctly you want to put static routes towards third party network and make it down when interface goes down.

If so you can achieve it like

> redistribute those static routes in eigrp with redistribute static option.

> If you are using ehternet interface for connecting 3-rd party network then those static route will not go away from routing table

   if remote interface will go down. TO acieve you need to have IP SLA with tracking option.

    Overview is given in below link

    http://www.ciscoblog.com/archives/2008/08/dynamic_failove.html

Regards

Mahesh

[Talha Ansari · Accepted solution]

Well there is a way.... What you can do is configure the route and associate it with a IP SLA.

Just for example :

Say you intend to configure a route as

ip route 192.168.1.0 255.255.255.0 172.168.1.1

You can track the reachability of the ip address 172.168.1.1 provided that ICMP is allowed for this IP

ip sla monitor 10
type echo protocol ipIcmpEcho 172.168.1.1 source-ipaddr src-ip-addr   --- this could be your own interface ip

track 10 rtr 10 reachability

ip route 192.168.1.0 255.255.255.0 172.168.1.1 track 10

What will happen is that your router will continuosly ping the next hop ip addr (172.168.1.1) and if the ping fails then the static route will be removed from the routing table.

Only those static routes are redistributed those are present in the routing table. So the redistributed route in the EIGRP would be removed when the SLA fails.

Hope that helps....

[BlueyVIII]

Thanks for the help so far guys, it's given me a good background to dig deeper.

What I have found is that the 4507's we're using don't seem to support the 'IP SLA' command. (IoS version 12.2(25)EWA14, RELEASE SOFTWARE (fc1)

Is there another way to do it?

[Talha Ansari]

Well there is a way... In the earlier days IP SLA was configured using some rtr commands... Try these commands if it works :

config t

rtr 10

type echo dest-ipaddr destinationipaddress

frequency 30

rtr schedule 10 life forever start-time now

track 10 rtr 10 reachability

ip route 192.168.1.0 255.255.255.0 Tunnel0 track 10

Suppose even if rtr commands is not suported on your device you may configure a GRE tunnel between your router and the neighbor router and manually set keepalives and configure the static route with exit interface as GRE tunnel... GRE keepalives are point to point and in this case suppose if the GRE keepalives are missed the GRE tunnel will go down and the static route would be removed from the routing table effective stopping it from getting redistributed. But offcourse you will have to convince the next hop guys to configure GRE at their end.