How to block emails with empty recipient address
Problem reported by Lennart Eliasson - 3/14/2026 at 12:26 AM
Submitted
I get a lot of spam with no recipient address.
How can I block them?
Douglas Foster Replied
Please clarify.  If no recipient, then the message would not have reached your server, and could not finish the SMTP command sequence even if it connected.  What exactly is blank?
Tan Replied
Can attach the email header to take a look at the From header?
Sébastien Riccio Replied
He probably means the To: header is missing or empty. This can happens for exemple if only Bcc: are supplied.

Sébastien Riccio System & Network Admin https://swisscenter.com
terry fairbrother Replied
Not tried this as I get very few 'blank senders', but content filter has this

then perform an action on the condition as needed. Might work, might not. But worth a try

Lennart Eliasson Replied
Yes Sébastien Riccio thats what I mean.

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