troubleshooting Question

Weird Cisco ASA Firewall and IIS interaction -- Server not responding through firewall after reboot

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MOS2008Flag for United States of America asked on
Microsoft IIS Web ServerCisco
8 Comments1 Solution618 ViewsLast Modified:
Hey Everyone,

I've finally got one that after almost 2 weeks of work on the issue, I'm turning to you all for help.

My situation is that, after recently rebooting a particular Win2003/IIS6 farm, I noticed that the servers stopped responding to HTTP requests. Of course, there is 4 servers in the load balancer, so I stopped after rebooting 2. I investigating the issue, and have not been able to get these two servers back up except by changing the NAT entry on the firewall to a different internal and external IP. Then it works again until I reset IIS, or reboot the server.

These servers have a considerable amount of small sites on them, 400+ I would say. Of course the MaxEndPoints Registry key has been tweaked, nothing has really changed.

The ASA's are 5540's in a high availabilty pair, running 8.0(2)k18 (I also tried 8.0(3))

We've reloaded the firewalls, the routers, etc, with no luck to this point, and we have several other IIS6 farms that were not affected at all, only this farm of 4 servers.

NMAP reveals this when hitting the servers that do not work:

Not shown: 1714 closed ports
80/tcp filtered http

Can anyone think of any reason at all on the firewall, that would cause it to stop responding, or show filtered on port 80? The other servers show 80/tcp OPEN http..

Thanks for any help, I've even hit Cisco TAC and Microsoft on this one with no results thus far. :(
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