two routes for the same subnet

[diesel786]

Hi all,

having some problems with the ISP...

One router is having two different routes for the same subnet

124.108.24.0 255.255.248.0 124.108.31.242(first)

124.108.24.0 255.255.248.0 124.108.31.246(second)

But when the first interface goes down the

traffic does not get pushed thru the second interface..

Help please

[sansarav720e]

Hi Ali ,

             Give me following things

1) when there is outage on 124.108.31.242 does your line protocol on your router interface goes down . when your line protocol or your physical interface is down your static route pointing to 124.108.31.242 will disappear from your  router routing table .

    If your line protocol is not going down during 124.108.31.242 link down ,then you static route will not disappear from your routing table . To make your static route disappear from your routing table during .242 outage , you can configure IP sla for ping response for this .242 address and you can  add track feature on your static route pointing to .242 ip address. which make static route disappear when ICMP reponse is failed from .242 address

If all things are happening properly your traffic is moved to second interface 124.108.31.246  ,but still you cant access the destination then check for below case

  check whether your 124.108.31.246 is having reverse route for your LAN subnet .

HTH

san

[diesel786]

thanks shantoshkumar,

IP SLA was one consideration but due to old IOS version it couldnt be activated, since its a production equipment the vendor doesnt want to change it.

Any other way of chucking the route from the routing table??

[sansarav720e]

Hi Ali ,

             In static routing there is no other option except tracking , else you need have dynamic routing to be enabled on router and your service provider router .

             As we could see 124.108.31.240 /30 , 124.108.31.244/30 is two subnets used between service provider and your router , you can ask service provider combine this 2'nos of /30 subnet into /29 subnets ,they can enable HSRP at their end and you can point VIP of HSRP as your gateway for this subnet . HSRP hello packets will be exchanged betwen your two links if there is any outage on links automatically another link will carries the traffic .

            This configuration is to be done at your service provider side , not on your side , HSRP VIP is your gateway for this subnet .

HTH

San