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New Member

Fast/Ethernet IP Help


I am new to cisco routing and I have a question.. Here is what we are intending to do.

We have two ISP's on two differnt Routers that they provided for our internet access.. The problem is, when one goes down, we have to manually switch them around and on our firewall to accomindate the backup.

That is a major pain! So what we're intending to do is using a larger router, merge both into one unit, then feed into the firewall and then into our network.

So far so good?

So I bought a Cisco 2620XM with two WIC cards for the ISP's. I have configured one WIC card sucessfully and can ping from within the router..

Now comes the tricky part..

In the past, we have always set the untrusted side of the firewall to one plus the fast ethernet port of the ISP's provided device.. Which works fine.. We increase the number by one and that becomes the managed IP address of the firewall.

But what do we set the fast ethernet port when we have two different T1 lines feeding into the same router? I know we can NAT across the router.. Is that the only option? If so, what is the syntax for that? If not, I would like to NAT on the firewall if possible.

Any help is appreciated!



Re: Fast/Ethernet IP Help

Check the link below for NAT . May be you have to look for Overlapping networks.

New Member

Re: Fast/Ethernet IP Help

as it turns out.. i got both ISP's to work on the router.. if i unplug one, the other takes over without any problems.

i can't nat at the router, because its a firewall/vpn device and the other offices that use it, need to be able to reach an outside address to establish a tunnel.

any other suggestions? do i need a firewall that can handle multiple interfaces? if so, what fireall will do that?