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Community Member

CSS 11503 Portmapper Error

Any idea what this error means? We saw this after we did some load testing this weekend.

DEC 11 15:35:26 2/1 150337 PORTMAPPER-6: FWMapPort - ERROR Couldn't Pick Port

I cannot seem to find reference to it.

Thx - Pat

Cisco Employee

Re: CSS 11503 Portmapper Error

This is a level 6 error, so not really a big error and more a information.

You probably have configured a group to nat source ip address.

This message is printed when the CSS was unable to select a source port.

It should normally retry and if it can find one the packet is forwarded.

If you get a lot of these, you may start dropping packets.

With group you somehow limit the possibilities of the CSS. If many clients are nated into a single ip address, the number of port will be limited to 65k and this will limit the number of active connections.



Community Member

Re: CSS 11503 Portmapper Error

We were simulating 2000 clients. I knew group would limit us, but I did not think 2000 clients (with an avg of 4 open connections) would be an issue.

Guess we need to look at doing passthru.


Cisco Employee

Re: CSS 11503 Portmapper Error

do you have ASR configured [stateful redundancy] ?

It is known to limit the number of ports available.

Anyway, it is a better solution to avoid source nating.


Thanks for rating.

Community Member

Re: CSS 11503 Portmapper Error

Yes, we are doing ASR and have split ports in half. We needed source/dest NAT so we could have direct access without going through the load balancers.


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