NAT Failover Question

Unanswered Question
Nov 12th, 2009
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I have an RV that we have dual connections out to the internet on. One is Cell, one is satellite. The Cell card is the primary connection with the satellite being the backup. I am trying to set it up to where if the cell card goes down the satellite automatically picks up which could possibly be happening but I have NAT statements for the two that apparently don't pick up because when I fail (shutdown) the cell card I can't get out to the internet over the satellite. This doesn't work until I remove my NAT statements. Any ideas on how to make the NAT pick up automatically? I have included what I think are the pertinent commands...

FA 0/1

ip address

ip route Cellular0/0/0 99 track 1

ip route 100

track 1 interface Cellular0/0/0 line-protocol

ip nat inside source list 110 interface Cellular0/0/0 overload

ip nat inside source list 112 interface FastEthernet0/0 overload

access-list 110 permit ip any

access-list 112 permit ip any

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Jon Marshall Thu, 11/12/2009 - 07:59
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The solution that springs to mind is to use an EEM script that tracks the interface and when it goes down the script then automatically clears the NAT translations.

If you post this into "Network Infrastructure -> Network Management" the Cisco expert on EEM, J. Clarke, should be able to tell you whether this is a workable solution.

Edit - if you do repost make sure to include IOS version as EEM capabilities vary according to IOS version.


dhopper82 Thu, 11/12/2009 - 08:05
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Thanks Jon. I will ask about EEM script on that. Upon initial look though I don't think that my 2811 I have in the RV is EEM capable. But I will ask that question.


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