Q: proxy setting? how?

SU always says the Apple SU Server could not be found.

Doublechecking, Allan. Is that Software Update on your Mac, or are you getting this when using Apple Software Update for Windows on a Windows box?

Apple.com > Support > Discussions > Windows Compatible Technology > Apple Software Update for Windows

Since we can go for months at a time in this forum without any original posts actually being about Apple Software Update for Windows, that doesn't count for very much I'm afraid ... Posts about the software that the forum is supposed to be for are quite literally the exception rather than the rule.

Unfortunately, I can't find straightforward documentation on ASU for Windows and proxies. Normally, I would expect the proxy settings in your internet options (the same ones that Safari for Windows uses) to apply for ASU.

Is the proxy server set up to allow ASU to make contact via TCP port 80? The following article says "Software Update" uses that port. (Fingers crossed that goes for ASU for Windows as well.)

["Well known" TCP and UDP ports used by Apple software products|http://support.apple.com/kb/TS1629]

This is Windoz we are talking about. There is no global proxy setting like there is for the Mac. Every program has to handle it themselves.

This is Windows we're talking about so that isn't true. In your Internet Options control panel, go to the Connections tab. You'll see the built-in Windows proxy settings that programs that don't install their own proxy set-up use. You'll see further options if you click the "LAN Settings" button in that tab.

Those are the proxy settings that Safari uses. (You'll find yourself in that control panel tab if you go Edit > Preferences > Advanced and click the "Proxies: Change settings" button.)

iTunes also uses those proxy connections, as per:

http://discussions.apple.com/thread.jspa?threadID=2345214

http://support.apple.com/kb/TS2367

But there's no profit in arguing about matters. I'll leave you in peace. Good luck with the support ticket.