topic Re: Cisco 2821 IOS Firewall and PAT issues in Network Security

Cisco 2821 IOS Firewall and PAT issues

bbrendon — Tue, 26 Mar 2019 00:39:36 GMT

I'm having two odd problems with a 2821 that is used as a firewall. I'll describe one of them.

Every few days, I can not access a server on the internet at port 1055. Running a 'clear ip nat trans *' does not fix the issue. Strangely enough, after reloading the 2821, access from the internal network to the internet server at port 1055 works again.

Additionally, while the problem is occurring, any other port that is listening on the internet server is accessible, just not 1055. A reload fixes the issue.

Also, sh ip nat trans only has about 1000 lines when the problem is occurring.

Any ideas what a permanent solution might be?

Re: Cisco 2821 IOS Firewall and PAT issues

rkalia1 — Tue, 22 Apr 2008 11:47:46 GMT

Check if you have setup low embryonic or max-connections on your access-lists somewhere.

rkalia

Re: Cisco 2821 IOS Firewall and PAT issues

bbrendon — Tue, 22 Apr 2008 15:18:01 GMT

neither of those exist in the router config

Re: Cisco 2821 IOS Firewall and PAT issues

smohanasundaram — Sat, 03 May 2008 04:43:11 GMT

which IOS you are using.update latest IOS first.its resolves some errors.

regs

S.Mohana sundaram

Re: Cisco 2821 IOS Firewall and PAT issues

bbrendon — Tue, 24 Jun 2008 22:10:25 GMT

Upgrading didn't help. The problem magically went away. I'm still not sure what changed. I narrowed it down to a handful of lines in the Cisco config, though none of them should have helped the issue from what I could tell.