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New Member

automatic failover from one interface to other

Hi,

We are using 1700 series router with 2 serial and i fastethernet interface.

currently connection is coming in via s0/0 (over frame-relay) and going out via F0/0 to the firewall.

What we want is if firewall goes down or the f0/0 goes down, router should automatically detect the network connectin problem and start sending the traffic coming in via s0/0 to s0/1 instead of f0/0( as this interface is down).

We are using OSPF as routing protocol.

Can anyone please help me that what should I do in order to configure this.

Thanks

1 ACCEPTED SOLUTION

Accepted Solutions
Silver

Re: automatic failover from one interface to other

When your F0/0 interface goes down, the routes, out this interface will be go down as well. You can simply have a floating route for same destination with higher metric cost pointing out via S0/1. As soon as FE goes down, traffic will be diverted to S0/1.

ip route x.x.x.x 255.255.255.0 f0/0 1

ip route x.x.x.x 255.255.255.0 s0/1 2

The above will not work if your FW goes down but not your f0/0. For that, use OSPF. If your FW is PIX, it supports OSPF.

HTH

3 REPLIES
Silver

Re: automatic failover from one interface to other

When your F0/0 interface goes down, the routes, out this interface will be go down as well. You can simply have a floating route for same destination with higher metric cost pointing out via S0/1. As soon as FE goes down, traffic will be diverted to S0/1.

ip route x.x.x.x 255.255.255.0 f0/0 1

ip route x.x.x.x 255.255.255.0 s0/1 2

The above will not work if your FW goes down but not your f0/0. For that, use OSPF. If your FW is PIX, it supports OSPF.

HTH

New Member

Re: automatic failover from one interface to other

Thanks for the response, it solved my problem. Just one more thing. I am using chekcpoint firewall and it supports OSPF, so if I enable OSPF on the firewall do you think if firewall goes down router will pick up the change in the network and start routing the traffic to the other interface.

Thanks

Silver

Re: automatic failover from one interface to other

Yes, if both routes are present with different costs, this is achieveable using OSPF.

Thanks.

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