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Why are emails blocked by postgrey even though it is whitelisted?

Lately, I received emails from a customer something like 12 hours later...

So I checked closer and could see that the email was from


On the server, I edited my whitelist to see what was going on:

vim /etc/postgrey/whitelist_clients.local

Searching the list I could see, so why is it that it gets bounced with a 450 by Postgrey if it is whitelisted?

Looking closer at the logs left behind by Postgrey, I found this line:

Apr 23 06:33:34 m2osw postgrey[1742]: action=greylist,

As we can see, the sender has an email address that says "".

Only, that's nice, but the Postgrey code actually makes use of the client_name parameter and there the domain is clearly

Here we go! I had to also whitelist The next very surprising things, though, is the fact that Postgrey would forget that is fine. I clearly had the default auto-whitelist turned on... Oh well, anyway, after adding that extra host, it works as expected.