HSRP WIth Dynamic Nat Or dynamic PAT

[studmuffin]

Is it possible to configure HSRP or some sort of fail over if you get a dynamic ip address with your two ISP's Using 2 4321 routers

[Richard Burts]

If we knew more about your situation we might be able to give better advice. But part of your question is easy to answer even with the very limited information that we currently have. HSRP on two interfaces assumes that they are in the same subnet and can communicate directly with each other. 2 routers connected to 2 ISP would not meet this criteria on their outside interface. They very likely might meet this criteria on their inside interface. But that does not address failover if one ISP has a problem.

[studmuffin]

The routers are connected to the ISP on the same subnet but the isp hands out its addresses via dhcp 

I currently have nat setup as this on both routers it is exactly the same 

I made and access list called interwebs that allows the networks i want to access the internet 

then the i made a command that says this ip nat inside source list interwebs interface g0/0/0 (the outgoing interface)

I have hsrp setup on that router and it works but the thing is when i test fail over i bring one of the interfaces down hsrp does its thing but i cant get to the internet after hsrp makes the standby interface active both routers can ping the internet it is just it cant do it when hsrp changes active wan ports

[studmuffin]

BTW this is done in packet tracer this is for a class project but we cant figure out how to do it

[Richard Burts]

Your original post clearly specified 2 ISP. Now you say it is really a single ISP giving addresses to both routers. That is a significant change. If both routers are receiving IP addresses in the same subnet then I would believe that it would be possible to configure HSRP on the interfaces. But whether it would work is problematic. Both Interfaces could participate in HSRP and have a common virtual interface address. But how would you get the ISP to use that virtual address? I am guessing that there is some other aspect of your assignment that we do not know about that would point toward a solution.

[studmuffin]

Im having trouble with nat that is the problem i am having HSRP works fine I just cant figure out how to get it to work with dynamic nat

[paul driver]

Hello
When you are running HSRP and NAT then you will need stateful nat with redundancy now depending on what software version you are running depends on the configuration because in later software versions NAT HSRP redundancy has been succeeded with cisco Box-to-Box nat (B2B nat) I found this out the hard way when i had statefull nat running on two boxes and then preceeded to upgrade them and got caught in a whole world of trouble? - lol

Can you verify what software version you are running on your rtrs?.

[studmuffin]

Im running the latest IOS version so how do i configure that i never even heard of it

[paul driver]

Hello

whats the model of your rtrs and the feature set running ?

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