[AusNOG] Assistance needed with Cisco NAT & Route-maps

[Jacob Bisby]

Hi All

Thanks for the help so far - it's now at the point where I feel like 
this needs to go on-list though.

The other's have so far helped me determine what the following line of 
config is supposed to achieve:

ip nat inside source static tcp PRIVATEADDRESS PRIVATEPORT PUBLICADDRESS 
PUBLICPORT route-map AAPT extendable

My initial question was what does the route-map statement achieve? I 
have never seen it put at the end of a "port-forward" before.

In this case, that route-map matches against a specific WAN interface, 
and an ACL that lists a whole bunch of private-subnets as sources to 
"any". It was explained to me that it's likely to be some form of 
destination based NAT but it has us a little stumped still. However the 
route-map actually does not look like it was designed specifically for 
this translation at all and is used in other contexts through-out the 
configuration.

Normally I would drop the topic here, re-do the config my way and be 
done with it. However, apparently Cisco TAC made this configuration and 
I'm not too keen on assuming they've done something wrong.

My question is - at what point would a dedicated WAN interface see 
(legitimate) inbound packets sourced from a private subnet? Can anyone 
shed a little light on what this may possibly be trying to achieve? I am 
limited in the configuration examples that I can give so apologies in 
advance.

Thanks

- Jacob
On 29/11/2013 4:44 PM, Jacob Bisby wrote:
> Hi All
>
> Looking for someone to ping me off-list - just need some quick 
> assistance / QA with some Cisco NAT / route-map config, have found 
> some config which I can't find any documented examples of and I'm not 
> entirely sure what it's achieving.
>
> Thanks in advance
>
> - Jacob
>
>
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