HSRP and static NAT theory

[ssteichmann]

I know that one can use the "redundancy" option on a static NAT to deal with duplicate IP messages when using the same NAT's on multiple HSRP routers.

I'm trying to think through when this should be necessary. Why do routers with duplicate NAT's, on the same LAN, complain about a conflict if only one NAT is in use? Shouldn't the backup router's NAT be dormant, since there is no traffic going through it?

The best I've found is this, which doesn't really help. The routers advertise the NAT?:

http://www.cisco.com/en/US/tech/tk648/tk362/technologies_q_and_a_item09186a00800a9679.shtml#q15

[tstanik]

Here is the configuration guide for the SNAT Primary/Backup. Follow the URL which will help you :

http://www.cisco.com/en/US/docs/ios/12_2t/12_2t13/feature/guide/ftsnat.html#wp1051530

[harmanrms]

Hi Ralph,

I need a help on configuring HSRP on SUP level on 2 of the 6513 switches. Can you help us to know how we can configure HSRP between two SUP32 or can you provide us a document that will help us to conigure it? Your reply on this will be really appreciated.

[ssteichmann]

Thanks for the reply, but unfortunately I couldn't find anywhere in that link where it might explain why two HSRP routers complain if they have the same static NAT's.