Domain Names/Static IP
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Visitor

Mails being rejected error 554

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

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Trusted Forum Contributor

Re: Mails being rejected error 554

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.
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New Member

Re: Mails being rejected error 554

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

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Visitor

Re: Mails being rejected error 554

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.

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Visitor

Re: Mails being rejected error 554

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

others. 

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.

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 is

kicked up to Tier 2 support level.

 

Maybe someone in this forum can get this done quicker for me.

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