Hi there, I've got a bit of a problem, hoping someone can help with troubleshooting.
We have a site with 50 or 60 workstations, all connected via a PIX 515e to a DSL line, and thus to the web. Intermittently, and seemingly randomly, workstations lose the ability to web browse.
Sometimes, after a period of time, they regain their ability.
Checking I've managed to do thus far involves pinging the gateway address and doing some nslookups to see what the boxes can see. Ping works okay, nslookup always fails.
The workstations are all configured correctly. Nothing changes on them, they just lose browsing ability. I'm starting to wonder if its the PIX, although nothing has really changed on its configuration. (Alternately, its the new version of Panda antivirus, which quietly installs a scanning web proxy on each client, but Panda are denying any responsibility.)
Does anyone have any ideas what I could check on the PIX while the problem is happening? I've tried some 'show arp' stuff to see if there's arp resolution, and that's okay, the ip of the affected machine is listed.
The PIX has an unlimited licence, so I dont think it should be denying connectins for any reason I can see.
As I said in another post, we saw a similar problem in the past. The PIX was not the culprit, but an ADSL router in front of it. The ADSL router did not let pass the packages with source port over 60000 or so. Is you have PAT configured on the PIX, this will be the case after some time running.
Check the traffic at the output interface in order to verify that the PIX is working fine. Then, check the traffic outside the router (trying to access a web server you possess) to see if the packets are transversing the DSL router.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...