Server Randomly Stops Accepting HTTP Requests - No Logs


We have a server that about once a week, stops responding to HTTP requests.

When we telnet to the IP on port 80, the second you hit any key on the keyboard it disconnects. In IE, you just get page cannot be displayed. Even when trying locally on the server itself, with public & I am, however, able to telnet to port 25 and connect to the SMTP server while this is occuring.

IIS Reset does nothing. There is nothing in any event viewer log that indicates any problems. The request obviously isn't logged in IIS logs either.

The only way to restore HTTP access is by rebooting.

This is a Windows Server 2003 Enterprise Edition server with SP2/R2. This server is part of an Active/Passive SQL Failover Cluster.

How can we troubleshoot why the server stops responding to HTTP requests?

How can we troubleshoot this when it is not happening? (just rebooted to fix)

I've put network monitor on the server but it doesn't appear to register any
connections on the IP, netstat doesn't show anything either.

I've just now put WireShark on monitoring all TCP/UDP Port 80 connections, but I suspect that when this happens it simply will not show up - then what?

Any insight would be appreciated,
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I have seen this happen when there is a leak in the non-paged memory pool on  the IIS server, only saw event logs if we left the server on for a day after IIS stopped responding

on one customers site it was due to a AV installation.

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anyoneisSoftware DeveloperCommented:
Could there be a port leak?


Sounds like intermittent DNS.

How many nics do you have on the server? Are the preferred DNS servers your internal DNS servers?
Also could something other than your Windows DNS server be supplying DNS, like  your router?
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brock_hensleyAuthor Commented:

Http.sys stopped accepting connections due to Non-paged Pool memory limit being hit.

Removed /3GB switch from boot.ini file to resolve issue.

As the the question posted was looking for "any insight" in the issue with the IIS servers lack of response, and my post pointed to the issue occurring because of low (leaking) "non-paged memory pool" with links to information on how to monitor the "non-paged memory pool" usage.  As the posters resolution to the issue also pointed to a non-paged memory pool issue, can I get a moderator review on this issue?
brock_hensleyAuthor Commented:
Pointed me in right direction, thanks.
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Windows Server 2003

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