A samba server with the name PIPE will silently fail many operation. Logging in works. Connecting and reading files on the server works. But browsing, neither workgroup nor shares does not work. This seams to be an internally used name for many functions, for example the $IPC service. One place were it fails is in smbd/ipc.c somewhere around line 551. Windows machines can be named PIPE without problems, so this must be an internal samba thing.
John, you want to document this ? I can't imagine that it will get high priority to be fixed.
I have added a note to the smb.conf man page "netbios name" section, with the warning not to use the name PIPE. - John T.