IIS6 is leaking IP address in header

This is my understanding of the issue so far:

• sc-win32-status 64 means “The specified network name is no longer available.”
• After IIS has sent the final response to the client, typically it waits for an ACK message from the client.
• Sometimes clients will reset the connection instead of sending the final ACK back to server. This is not a graceful connection close, so IIS logs the “64” code.
• Many clients will reset the connection when they are done with it, to free up the socket instead of leaving it in TIME_WAIT/CLOSE_WAIT.
• Proxies tend to do this more than others do.

Update: I found some interesting information here and here, so I basically re-wrote the page to ensure there wasn't any bad markup etc. and... the problem is now gone! It was just a shot in the dark, and I couldn't definitely say what it was that fixed the problem, since it was only affecting some of our clients under some very specific circumstances...

The only thing is that you're not saying "all addresses should have access" -- that's done in your firewall(s) and/or the server software and/or other security layers like tcpwrappers.

0.0.0.0, in this context, means "all IP addresses on the local machine" (in fact probably, "all IPv4 addresses on the local machine"). So, if your webserver machine has two IP addresses, 192.168.1.1 and 10.1.2.1, and you allow a webserver daemon like apache to listen on 0.0.0.0, it will be reachable at both of those IP addresses. But only to what can contact those IP addresses and the web port(s).

Note that, in a different context (routing) 0.0.0.0 usually means the default route (the route to "the rest of" the internet, aside from routes in your local network etc.).