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IP and DSL

I need a solution, currently we have a Cisco 7000, with 4-port ethernet, and serial interface. Currently my customer has DSL link, with a ip-subnet range from the isp, which the DMZ, each host has a fixed internet ip address from the range.

For redundancy my customer requires another DSL link, but he wants to use the same router (cost cutting), the DSL will be from another ISP, so the IP Address range will change. I want to use HSRP on the same router with different ports? also how do i manage to present the same ip address to the rest of the internet if the DSL link fails and then I am on another DSL subnet??




Re: IP and DSL

Well you are not going to actually be able to configure HSRP as you need two routers for that. There are however two ways that you can somewhat accomplish what you want. There is no way that you can have the users go out to the new DSL provider with the IP addresses of that the old gave. What you can do is configure NAT with two different pools(one pool consists of the 1st ISP's address block and the 2nd would consist of the new ISP's address block) and apply route-maps to the NAT. You would have to reassign your users some private IP's for this scenario.

The second thing you could do is keep the users IP's the same and configure only one pool with the new ISP's address block and configure NAT on the new DSL interface. You would of course need to add a new default gateway pointing to the new ISP as well. This would make all the users go out to the new ISP looking like the new ip addresses. Here is a URL for the configuration of general NAT

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