Question
Why does IMAil refuse mail with an empty sender address?
Here is an example transaction:
220 X1 NT-ESMTP Server mailhost.directlink.net (IMail 6.05 1039005-4) mail from: <> 501 bogus mail from quit 221 Goodbye
Answer
IMail Version 4 onwards has a setting "Refuse NULL <> Senders"
If this seting is enabled in IMail (some versions enable it by default) then all mail with an empty sender address will be rejected.
Internet standards require that mail servers accept e-mail with an empty sender address, i.e.,
MAIL FROM:<>
RFC821, section 3.6 says:
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:<>
RFC1123, section 5.2.9 says:
5.2.9 Command Syntax: RFC-821 Section 4.1.2 The syntax shown in RFC-821 for the MAIL FROM: command omits the case of an empty path: "MAIL FROM: <>" (see RFC-821 Page 15). An empty reverse path MUST be supported.
The developers of IMail software freely admit that this setting breaches the relevnt RFC’s for mail, see http://support.ipswitch.com/kb/IM-19980116-DD02.htm
Keywords:IMail, reject, ipswitch, post