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LetterpartFlag for United Kingdom of Great Britain and Northern Ireland

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Reverse DNS error from remote hsot but all checks show I pass

Hi,

we have recently moved office and servers and now I get the following from a remote mail server when we try and email a user there.


mx7.freeparking.co.uk gave this error:
"E5:Mail rejected because 178.251.239.149 doesnt have valid Reverse DNS."

When I run a DNS check at: http://www.intodns.com/letterpart.com

It's coming back showing that my Reverse PTR is ok.

Your reverse (PTR) record:
152.239.251.178.in-addr.arpa ->  mail.letterpart.com
You have reverse (PTR) records for all your IPs, that is a good thing.


Now. 178.251.239.149 is the IP address of the Exchange server but 178.251.239.152 is the gateway it sends through and what all tests, pings and sites show as the IP my server is sending from.

When I originally had 178.251.239.149 as the Reverse PTR. All the tests I ran showed it as failing so we had it changed to 178.251.239.152

Why is this one mail server complaining about my PTR while everyone else is happy and do I need to have 178.251.239.149 added as well to make it happy?
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Ben Hart
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ASKER

Hi ubadmin

So my PTR is correct as I thought? I shouldn't then be getting errors from hosts expecting it on a different IP.

Open relay: So far all my checks show that I might be an open relay but when I checked the default receive connector I don't have "Externally secured" ticked on Authentication which is what I understand to be the correct way to do it?
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