Our windows 2003 server has stopped all connectivity.

It's on Our firewall is

Attempting to ping the firewall returns "destination host unavailable". It was routing fine last night - no changes have been made to our firewall/router (which is one hop away).

I've rebooted the Windows machine to no avail.

Here's some information about the Windows server:

  • It can ping itself
  • The NIC looks fine in device manager
  • Link light and activity light are active on NIC
  • Ethernet connection in Network Properties shows status as Connected.
  • Swapped ethernet cable to no avail

Here's what isn't working:

  • Connectivity from the server to other hosts (including the same subnet).

There's no suggestion of the cause in the error logs (there are reports of failed services that depend on connectivity such as the time server)

  • 1. Can you post the contents of the route print command (just the IPv4 part)? 2. Can you check in your event log and post any error or warning entries you see? – Adam Brand Jul 14 '09 at 1:09
  • Is it 1 hop to your firewall, I assume it is as they are on the same subnet. If not, can you post the results of a tracert to it? Can you ping any other machines on the same subnet? – MDMarra Jul 14 '09 at 1:14
  • Also... assuming that you can ping from your ROUTER... can your router ping the server? Just want to try both ways to be sure. – KPWINC Jul 14 '09 at 1:15
  • Are there any other machines on the same subnet, and can they ping the router and/or the server? – AudioDan Jul 14 '09 at 1:16
  • thanks everyone! sorry i didn't add these things when reporting the issue. – chickeninabiscuit Jul 14 '09 at 1:19

Has it got the DNS server installed and did it happen after a reboot?

If not ignore the rest of this, but if so note that there is a bug in W2k3 that the DNS server can grab port 4500. This stops the IPSEC service runing and blocks all network access to and from the server. The immediate fix is to restart DNS then restart the IPSEC service (or of course restart the server). A longer term solution is to add 4500 to the reserved ports in the TCP/IP service parameters.


Re the DNS problem:

See http://support.microsoft.com/kb/956189

This refers to SBS, but it applies to standard W2k3 as well. I have been bitten by this several times and the fix described in the KB article works. I now routinely do this on all W2k3 installations.

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  • Yes it does have a DNS server installed! Do you have any further links to this bug John? Thanks! – chickeninabiscuit Jul 15 '09 at 5:35
  • For the link see my edit above. – John Rennie Jul 15 '09 at 7:57

Perhaps a dumb question - but have you tried a shut down and startup. Actual power the server down and then starting it up again? What do the system logs show?

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My solution was to reinstall TCP/IP. Apparently the TCP/IP stack was in some way corrupted.

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