A internal LiveUpdate Administrator 2.3.2 or earlier server was set up to provide definitions and other content updates for several Symantec products on the company network.  This LUA 2.x server downloads materials from Internet-based source servers, and reaches the Internet through a proxy server.  Initially all downloads were successful, but after the old MS ISA proxy server was replaced with a new Squid proxy server, downloads fail.  Valid details for the new squid proxy server are correctly configured in the LUA web interface.  

Testing connectivity from Configure > Source Servers shows that the connection failed ("Connection to Symantec LiveUpdate failed.")

Examination of the catalina logs shows that LUA 2.x is still attempting to use the details configured for the original ISA proxy server.

This issue is resolved with LiveUpdate Administrator 2.3.3.  Please upgrade to this or the current latest available version.

Should it not be possible to immediately upgrade, there is a known workaround:

After any changes are made to the proxy configuration (Configure > Source Servers), do stop and restart the LUA Tomcat service of the LUA 2.x server.  This will confirm that new credentials and other details about the proxy are in effect at all levels of networking.  Applying the changes within the LUA GUI is not immediately adequate.

The LUA Tomcat service can be stopped and restarted from services.msc or by command line.  This same stop and restart will be accomplished by rebooting the LUA 2.x server.