Question

Multiple PTR (reverse DNS) Records (Postfix)

Postfix is setup on my droplet where multiple domains (sites) are hosted. When sending some transactional emails from sites, they bounce to certain recipients though.

From the mail.log (redacted), “… (host mx.bt.lon5.cpcloud.co.uk[65.20.0.49] refused to talk to me: 521 smtpin48.bt.ext.cpcloud.co.uk Service not available - no PTR record for xxx.xxx.xxx.xxx)”

Now, my understanding is that you should only create single PTR records so am a little unsure of how to proceed?

I am aware of one option is to use an external service like Mandrill or SendGrid but would like to know what my options are for keeping my emails being sent from my droplet. Thanks!

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You can set the droplet’s hostname (which would update the PTR record along with it) to e.g. mail.yourdomain.com where yourdomain.com is one of the domains on that droplet, and then add an A record for mail.yourdomain.com that points to your droplet. <br> <br>This way it’s a valid PTR <=> FQDN setup and it will work fine for all of the domains on that droplet.

I have multiple websites running on each droplet though. <br> <br>If I understand what you are suggesting, while this would solve the issue for one domain the others would still suffer. <br> <br>Thanks for spending so much time on this though BTW.

Hello,

As per this comment here, you can set the Droplet’s hostname (which would update the PTR record along with it) to e.g. mail.yourdomain.com where yourdomain.com is one of the domains on that droplet, and then add an A record for mail.yourdomain.com that points to your droplet.

This way it will be a valid PTR <=> FQDN setup and it will work fine for all of the domains on that Droplet.

As a side note, I could also suggest checking this discussion here on why adding multiple PTR records is not recommended:

https://serverfault.com/questions/618700/why-multiple-ptr-records-in-dns-is-not-recommended