I am having issues updating some 2008/R2/2012 clients in an environment where this has never been an issue. 2003 clients have no issue.
We have a WSUS server and unrestricted access to WU. Simplish network; Server > Switch > Router > Internet.
Updating from WSUS has worked fine, forever. As has updating from WU. We typically select "Check for updates from Microsoft Update" and just use WSUS to record status. WSUS makes a fine fall-back though.
The last few weeks though, both have been failing. On about 15 servers (about half of the servers I've tried), I've gotten a few errors - ex: 80070643 and 80243004. The best I can get is after repeatedly checking for updates, sometimes I can get a few going at a time. These errors just seem like general inspecific errors, I don't think there is an issue with the servers themselves. DNS maybe?
Restarting or flushing DNS hasn't helped.
Any suggestions?
EDIT: I know this isn't the most detailed question, but I'm having a hard time finding a common theme - I get different errors for different updates and different results on different servers.