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Endless Grey-Listung 451 Try again later

Posted: 2019-08-21 06:00
by laskowski
Hello,
on my work I have a payed account at a *.outbound.protection.outlook.com server.
It is connected with my business email Adress.

If I sent an email to my private hmail-server-domain with enabled grey-listung, the frist try of the delivery will be answered with 451 please try again later.
That is as it should work.

But now Microsoft-Server (outlook.com) tries to deliver with an other IP.
And one again the hmailserver answeres 451 please try again later.

So sorry but that is endless !
Microsoft sends from 40.107.0.0 in a Class B size. So thexy try to reach my hmailserver from 254*254 = 60 000 different IP Adresses.
Until the same IP is tried for happenstance the hamil always does what hmail is supposed to do. "451 please try again later"

What may I do ?
The Microsoft does not habe an SPF Record because i habe set up an greylist exemption while SPF record is set.
Please Help,
The emails nearly do not reach my hmail anymore.

Re: Endless Grey-Listung 451 Try again later

Posted: 2019-08-21 06:21
by mattg
That's what greylisting does

You can elect to bypass greylisting on SPF pass, and that will allow that mail to come through
You can script a fancy Just-in-time solution, OR
You can switch off greylisting

Just remember that spammers set spf records too, and that the fancy scripting is likely to require a custom build at the moment (soon to be in a mainstream version - hMailserver 5.7 )

Office365 and Google hosting millions of domains is one of the many reasons why greylisting isn't what it used to be.