Refuse Null Senders
If you set the IMail registry to "refuse NULL senders", IMail Server refuses to accept mail if no address is specified in the "MAIL FROM" line of an incoming message (the null address (<>) is used).
Allowing no address in the MAIL FROM line makes it easier for spam mailers to send bulk mail to your users. However, note that RFC 822 requires that mail servers accept mail that has no address in the FROM line.
| Note: Microsoft Exchange uses the null address for messages from the postmaster. Enabling this command prevents deliveries of mail from Exchange postmasters. |
- Locate the following string value:
HKLM\system\currentcontrolset\services\smtpd32\parameters\RefuseNullFrom
- Set this to 1 to enable this feature.
