> I'm getting a lot of bounces to postmaster from some dumb
> mail client that isn't setting the To: or From: headers.
> I tested this out:
>
> telnet localhost 25
> MAIL FROM: <>
> RCPT TO: <>
I can't speak to the "RCPT TO", but "MAIL FROM: <>" is legal and is
the method RFC 821 suggests to keep bounces from bouncing:
"Section 3.6:
...
This notification message must be from the server-SMTP at this
host. Of course, server-SMTPs should not send notification
messages about problems with notification messages. One way to
prevent loops in error reporting is to specify a null reverse-path
in the MAIL command of a notification message. When such a
message is relayed it is permissible to leave the reverse-path
null. A MAIL command with a null reverse-path appears as follows:
MAIL FROM:<>"
Some sites have started disallowing this as an anti-SPAM measure.
Personally I think that is more trouble than it is worth.
--
gowen -- Greg Owen -- [EMAIL PROTECTED]