IMail - 501 bogus mail from in SMTP log

SMTPD (004C0376) [200.231.198.120] bogus address in MAIL FROM:<>

What does it mean?

Answer/Solution: This means that the option "Refuse mail from NULL Senders" has been enabled for the SMTP service.

In versions 8.10 and later, this option is no longer configurable in IMail Administrator. Run regedit. Go to:
HKLM\system\currentcontrolset\services\smtpd32\parameters
Set the value 'RefuseNullFrom' to 0.

Stop and restart the SMTP service after a change.

In version 8.0x, the “Refuse mail from NULL Senders” option is found on the Advanced tab in IMail Administrator:

In version 7.15 and below this option is on the SMTP Security tab.

Do not use this option if you wish to receive mail from postmaster accounts on other mail servers that send all messages with a NULL From field. Having this option checked prevents your users from getting bounced messages back from postmasters. In addition, if you wish to receive Read Receipts (these verify that a message sent was received and read by the recipient) they are also sent with a NULL From field; you will need to make sure that this option is not checked.

If the “Refuse mail from NULL Senders” option is enabled it checks the actual sender in the SMTP envelope--the "MAIL From:" field. (Senders can set the "From:" field in the message envelope to anything they want.)

Note: Strict compliance with the SMTP RFCs does not permit the "Refuse NULL <> Senders" option. To comply with the SMTP RFC, the “Refuse Null <> Senders” option should not be selected.