My company is making everyone upgrade to the latest Symantec firewall/antivirus combo. The upgrade to Symantec Client Security worked fine on my desktop (other than the three reboots required to uninstall the existing antivirus and firewall pieces), but weird things started happening on my laptop after I upgraded.
The first thing I noticed happening was that Gmail Notifier couldn’t connect. It kept failing to connect to the server, returning error 12029, “Can not log in to mailbox”. Firefox could open Google Mail without a problem, but Internet Explorer could not. I looked in the new firewall log to see if some new rule was messing things up, and sure enough, access was being blocked due to the rule “Block access to secure sites”. That turned out to be a spectacularly unhelpful rule.