there's this little, seemingly trifling, setting in the context dialog box of a computer discovery rule. it reads like this: during computer discovery, contact each computer to verify that it exists.
if you're wondering what this setting does, it's been purported that when it's enabled, the management server attempts to connect to the machine defined in the rule through the ipc$. i haven't fired up a network sniffer to confirm this allegation. if anyone has, please do comment!