Static confusion

[d.hardy4]

The problem I have is as follows:

Site A

Internet connection – ISP A

Firewall (non cisco)

Cisco 3620 router connected to a Frame network

Site B

Internet connection – ISP B

Firewall (non cisco)

Cisco 3620 router connected to a Frame network

Site B ISP link is new and will be used as a backup should Site A not be available. The Frame element is working fine. I have a server on the DMZ at both site (yes Site B has all that Site A has) this does our email virus checking/filtering etc, while B is not processing Live mails it is switch on and working so it tells us when it has updated virus sigs etc. What it couldn’t do was to send this to the internal mail server at site A as it did not know how to route there.

So I have put the following static routes on each of the 3620 router

Site A:

Ip route xxx.xxx.114.100 255.255.255.255 10.10.20.10 (where 10.10.20.10 is the number of the frame circuit)

Site B:

IP route xxx.xxx.114.100 255.255.255.255 10.205.0.254 (where 10.205.0.254 is the LAN side of the firewall and xxx.xxx.114.100 is the ISP B public IP address)

This was working fine internally so it looked good. But since doing this we have a problem sending mail to one domain it works out they have the same IPS as our B site but a further subnet. xxx.xxx.107.1.

When we ping or trace it comes back destination host unreachable, if we remove the static routes it works fine.

So the question is how can I get this working/what am I doing wrong.

Thanks for any help.

[Harold Ritter]

It sounds like you might need to configure "ip classless" on the 3620s.

Hope this helps,

[d.hardy4]

Yes one of them is set to no IP Classless, what does this command do?

Thanks

[d.hardy4]

By the way, its has fixed my problem.

Thank you.

[d.hardy4]

By the way, its has fixed my problem.

Thank you.

[Harold Ritter · Accepted solution]

With "ip classless" the IOS will forward the packet to the best match either it is within the scope of the majornet or not.

With "no ip classless" the IOS will forward the packet to the best match within the scope of the majornet. This means that if you don't have a match within the scope of the majornet, the packet is dropped even if you have a default gateway installed in the RIB.

The default has been changed from "no ip classless" to "ip classless" in recent IOS versions.

I'm glad I could help,