I'm experiencing a frustrating issue with our email setup and could really use some guidance. My company uses Office 365 for email and we also have a Barracuda web spam filter to manage our spam. We route all inbound and outbound emails through Barracuda. To send emails from devices like multi-function scanners, we have a Postfix server running onsite. The process goes like this: the scanners send the email to Postfix, which then forwards it to Barracuda, and finally Barracuda sends it on to O365.
We have two different ISPs for redundancy—Spectrum Business as our primary and AT&T Business as our secondary. The problem arises when our internet connection switches to AT&T: any emails forwarded by the Postfix server are blocked by Barracuda, which cites "Message was blocked due to No PTR record."
I've provided examples of a blocked email and a successful one. Both use Postfix, but the one that works comes from the Spectrum IP while the blocked one comes from AT&T. I have all the necessary SPF records set up, and I did create a DNS record for our Postfix server linked to AT&T's IP. I'm just lost as to where to go from here—should I be looking at the Postfix configuration file, the DNS records, or Barracuda's settings? Any help would be greatly appreciated!
2 Answers
Check your MX records to see if they're correctly set up to allow both IPs to send emails on your behalf. This could be a simple fix where your AT&T connection isn’t authorized to send through Barracuda. There may be an IP allow list that you need to add the AT&T IP to. That would be a good place to start looking!
You definitely need AT&T to create a PTR record for you—that's essential since they own the IP address. It's not something you can set up on your own, so reach out to them and specify you need a PTR record. Just Google "PTR record" for more context if you need it. Good luck!
Thanks for the tip! I tried to create one through the AT&T Business Center but hit a dead end. I found an email address online and sent them a message. Fingers crossed!
I have an MX record that lists the AT&T IP, so that should allow the IP. Barracuda does reference the records, but I'll double-check everything. I've also reached out to AT&T for the PTR record after your suggestion. Thanks!