Why does mail get rejected by IMail?

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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
221 Goodbye


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.,


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:

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

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