Stan is exactly right. The following is also from RFC822 (sec 1.1 Scope). We should remember where SMTP leaves off and vendor software implementations pick up. That point is the interface between SMTP and the local MTA (message transfer agent) implementation. In fact, this is the case with almost all TCP/IP standards. Rarely do they dictate a local implementation. The confusion arises when we forget that. Don RFC822, sec 1.1 Scope, in part: Some message systems may store messages in formats that differ from the one specified in this standard. This specifica- tion is intended strictly as a definition of what message content format is to be passed BETWEEN hosts. Note: This standard is NOT intended to dictate the internal for- mats used by sites, the specific message system features that they are expected to support, or any of the charac- teristics of user interface programs that create or read messages. -----Original Message----- From: Stan Ryckman [mailto:[log in to unmask]] Sent: Monday, September 30, 2002 2:38 PM To: [log in to unmask] Subject: Re: Dupe entries on 1.8d ...... Huh? WHAT implementations ignore this? Remember, the RFC says the addresses JOE@... and joe@... are distinct, but it does NOT specify whether they map into distinct mailboxes. Newer systems seem to map all cases into the same mailbox, but that's just a (permitted) choice, ....