Mails being rejected error 554

Question

Hi, 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? Thanks MIke

train_wreck · Answer

Is your mail servers IPv6 address 2601:283:c200:ec00:6e3b:e5ff:fe51:4b79? If so, then both the Comcast DNS servers and dnstoolbox.com both report no PTR. That address looks like a dynamically allocated delegated prefix addres, which is what you would get plugged into any of the leased coax-based gateways. At this time, there is no way to create reverse DNS records for these addresses. Static v6 is coming this year, and i have to assume that v6 PTRs will be available then.Keep in mind that PTRs for static v4 addresses are different.

michaelcoffin · Answer

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. -Mike

phantomco · Answer

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.

lonnieb554 · Answer

I have experienced this same issue.  And the problem has been compounded nowto include aol.com email addresses as well as 1and1.com and comcast.net.  Theseare the ones that I my users are receiving bounce messages from.  I suspect there may beothers. After hours and days of troubleshooting and back and forth with customer service.  I found that the PTR recordswork best when the IP points to the host server with the following format.123.123.123.123           mail.domain.com 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.123.123.123.123          www.domain.com.123.123.123.in.addr.arpa 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 iskicked up to Tier 2 support level. Maybe someone in this forum can get this done quicker for me.

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