Mobility • Re: Strange smtpd hostname lookup error against Mobile users ISP

Thanks for the replies and information.

The users are connecting on port 587 for email submission/sending email. Not sure why this would cause this issue?
We have a cloud based email filter in front of our mail receiving on port 25, so no direct access for incoming mail, but that is not an issue here.

I think he uses it incorrectly.

Not sure what you mean by using this incorrectly.

In Postfix this is "reject_unknown_client_hostname" in your smtpd_client_restrictions,

I will look into the "reject_unknown_client_hostname"

And/or you can ask the ISP to get their reverse DNS straight

I don't know if Elon will be very responsive to this request.

I think the issue is the client hostname lookup, just seems odd there would be a DNS lookup against the connecting client's host/ISP, in order to send email. Not that I haven't seen strange things before.

Statistics: Posted by grantntourbus — Tue Jan 09, 2024 6:35 pm

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