Receiving this error on mail being sent to Comcast:
SMTP error from remote mail server after initial connection:
host mx1.comcast.net [2001:558:fe16:1b::15]: 554 resimta-po-06v.sys.comcast.net comcast 2601:283:c200:ec00:6e3b:e5ff:fe51:4b79 Comcast requires that all mail servers must have a PTR record with a valid Reverse DNS entry. Currently your mail server does not fill that requirement.
We have a reverse on our mail server, which is sitting in our building on a Comcast connection. Not sure what else I need?
Was this resolved for you Mike? I'm having the same problem, started at the end of July, only impacts outbound emails to Comcast.net recipients.
No, I've reposted it again. I'm not really happy about this and it's becoming more of a problem.
Difficult to believe that they can't set their servers not to reject their own network.
I have experienced this same issue. And the problem has been compounded now
to include aol.com email addresses as well as 1and1.com and comcast.net. These
are the ones that I my users are receiving bounce messages from. I suspect there may be
After hours and days of troubleshooting and back and forth with customer service. I found that the PTR records
work best when the IP points to the host server with the following format.
Since I have several servers on different Comcast subnets, I have been able to experiment with the issue.
I still have the issue with one subnet due to the way that the Customer Service Reps input the info.
I provided them with host names and I wind up with the following.
Some recipient servers (such as aol.com) reject mail if the rDNS returns with .in.addr.arpa in the address.
These servers are looking for only a FQDN or host name in the response.
I would think it would not be so hard to get this corrected but what I have found is that it only gets corrected when it is
kicked up to Tier 2 support level.
Maybe someone in this forum can get this done quicker for me.