The Issue

We have a website that sends email using php mail function and sendmail. We frequently get email rejected response emails from several destination email servers saying that we have an issue with our ptr record.

Current Environment:

The mx record for the websites domain name points to the google mail servers and works fine for sending and receiving mail in smtp/pop clients.

When doing a reverse lookup using nslookup the ip does not resolve to any domain name.

Note: There are multiple websites hosted on the same server using the same ip address, and the servers MAIN domain name is serv1.rhinoagile.com


but when the website uses sendmail to send out email we get the resposne mentioned above about the reverse dns issue.

My Question: Can I... ?

can I leave the mx records as they are and add a ptr record resolving the websites ip address to serv1.rhinoagile.com (because the IP is used for multiple sites, I don't want to have the ip reverse to any specific websites domain name)

Not an option...

Configuring the website to use smtp is not currently an option. It is not currently built into the cms platform, and I do not have approval to add the ability to use smtp to the cms at this time


If you are famillilar with digital ocean, It would be nice if you could also advise me on how to do it in their interface, otherwise I will just google it.


Classic first suggestion:
Make sendmail at the web host send outgoing email via another mail server (smart_host). The relay server will be able to use properly configured PTR-A loop.

You may use mailertable to set direct or via relay delivery on per destination domain basis.

mailertable file:

# send directly to example.net and its subdomains
example.net   esmtp:%0
# send via smarthost.example.com messages to example.org
# [] are used to diable searching for MX records
example.org   esmtp:[smarthost.example.com]
# default route - may be used instead of default smart_host for all outgoig mail
.   esmtp:[smarthost.example.com]
  • If I understand correctly, I would configure it to send through googles email servers by configuring sendmail. If id do that then would the other websites on the server, whom do no not use google as their email provider, then fail to send? – Cory Baumer Oct 21 '13 at 19:49
  • The suggestion above would do the same email routing for all hosted domains. It possible to make sendmail route outgoing messages based on SENDER email address but treat it as the last resort option. 1) Can you define email sending program on per hosted www domain basis? 2) Can you run every www domain script as different OS user? [It is possible with apache but it is usually avoided] – AnFi Oct 21 '13 at 22:37
  • I'm choosing this answer because it would have been a good solution for me. However I did end up getting approval for development time so I just added smtp abilities to the cms using swiftmailer (php) – Cory Baumer Oct 23 '13 at 16:43

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