As viruses, Trojans, and worms become more dangerous, antivirus software get more sophisticated. Back and forth it goes, and at some point something's going to break. It's not necessarily a bug, but NAV's methods are confusing users and angering ISPs.
Users first notice the problem when they try to retrieve e-mail.
Obviously, that's not the name of a normal ISP's POP3 mail server. You'll find that the POP3 mail server is one of those listed above. And as long as Norton AntiVirus is working correctly, this configuration should work fine. Once a malicious piece of e-mail shows up in your inbox, antivirus programs will flag it, but it's often too late to prevent damage to the system. Instead of catching the viruses after they infect your system, NAV creates a virtual inbox called pop3.norton.antivirus where the e-mails can be scanned before they reach your email program.