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Reverse DNS does not match SMTP Banner

Hello everyone,

After 02 months, my ISP finally helped me with Reverse DNS / PTR records. Now when I test my email server on MXToolBox, it states the following error on MXToolBox:

1- Reverse DNS does not match SMTP Banner

My email client is also not able to login to the IMAP. Previously, the email client could login to both IMAP/SMTP and only email was being rejected due to no PTR record.

I believe the tech guys at ISP didn't enter it correctly. The domain is caretakers.pk

Any help would be highly appreciated!

Thanks and regards,
Watch Question

Top Expert 2014
Generally, don't worry about the MX Toolbox check as it is incorrect for Exchange servers after 2003, since it checks the receive connector instead of the send connector.  But you haven't mentioned what your email server is.

Instead as verification, you can see what SMTP banner you're using when sending by sending an email to helocheck@abuseat.org and you will get a reply with the info.  See here for info:  https://www.abuseat.org/helocheck.html

The FQDN used in the banner should match an A record which points to the IP used to send.  And the PTR record for that IP should point back to the same name.  From what I can see looking at your domain, the DNS appears to be set correctly (using the name mail.caretakers.pk).  You will have to check the SMTP banner yourself.
MASEE Solution Guide - Technical Dept Head
Most Valuable Expert 2017
nociSoftware Engineer
Distinguished Expert 2019

This is looking good as long as your mailserver uses mail.caretakers.pk in its HELO/EHLO message when sending mail.

~ $ dig +short MX caretakers.pk
5 mail.caretakers.pk.
~ $ dig +short mail.caretakers.pk
~ $ dig +short -x

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This does not help:
~ $ telnet mail.caretakers.pk 25
Connected to mail.caretakers.pk.
Escape character is '^]'.
220 srv.caretakers.pk ESMTP Postfix
221 2.0.0 Bye
Connection closed by foreign host.

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As your server calls itself srv.caretakers.pk not mail.caretakers.pk...
Obaid ur RehmanTechnical and Operations Manager


All of the input from experts was helpful. So I waited for a day, tested again and now it is working like a charm!