Monday, February 9, 2015

Windows Server Unable to Make Outbound TCP Connections

Ran into an issue with a customer server where various things were just not working. A reboot always fixed it, but it had to be done every few days which was not acceptable. The types of errors being received were things like "no logon servers are available" or being unable to open any Active Directory tools. DNS and network shares were working fine, i could RDP in without issues, restarting various services did not help, ICMP/UDP were fine. I attempted to telnet out but any outgoing connection was immediately aborted, wireshark did not see the connection attempt, all firewalls were off.

I ended up putting PuTTY on the server and tried to telnet from there, and received a more specific "no buffer space available" error. Searching for that, i determined it was a Winsock error related to not enough free handles being available. With that knowledge, i opened the task manager and added the Handles column and sorted. There it was, an HP Plotter utility service with 6000+ open handles. I killed the process and everything immediately went back to normal.

1 comment:

  1. Thanks Mike this solved our problem! Not with the HP utility though.

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