I have a DOS process running in XP Pro SP2 that does the following...
NET USE LPT3 \\pcname\prtshare
TYPE mydoc > LPT3
NET USE LPT3: /DELETE
The net use commands work. But sending information to the now mapped LPT port gets 'Access is denied'.
Windows, from any computer, has no issues printing to the shared printer. Locally the shared printer is connected to LPT1. DOS can print to the LPT1 port. However even on the local computer trying to print in DOS to the mapped LPT3 gets access denied.
I'm signed in as admin and the printer has full access granted to everybody.