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frankcastle's profile

New Contributor

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2 Messages

Fri, May 31, 2019 10:00 AM

unable to send email to comcast.com addresses

I have my own private mail server which is able to send mail to just about anyone.  One key exception is any address at comcast.com.  I can send mail to comcast.net addresses but not comcast.com for some reason.  I am not listed on any known blacklists.

 

$ telnet mx1.comcast.net 25
Trying 96.114.157.80...
Connected to mx1.comcast.net.
Escape character is '^]'.
220 resimta-po-28v.sys.comcast.net resimta-po-28v.sys.comcast.net ESMTP server ready
quit
221 2.0.0 resimta-po-28v.sys.comcast.net resimta-po-28v.sys.comcast.net closing connection
Connection closed by foreign host.

 

See that works fine.

 

$ telnet mx20.comcast.com 25
Trying 162.150.44.70...
Connected to mx20.comcast.com.
Escape character is '^]'.
554 5.7.1 You are not allowed to connect.
Connection closed by foreign host.

 

They don't provide any details for why I am not allowed to connect or any instructions on how to remove this restriction.  I am hoping someone out there can help me get this resolved.  Thanks in advance!

 

Official Employee

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412 Messages

3 y ago

Ah, thank you for reaching out about this! Actually this is a fairly simple explanation; the @comcast.com emails are for internal employees. The email addresses for customers are @comcast.net which explains why yours are getting bounced back from the .com. It's working as it should be, so if there are any other questions or concerns that we can help out with please let us know! 

New Contributor

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2 Messages

3 y ago

Thanks for responding, Gina.  Are you absolutely sure that is the case?  I have some comcast.com addresses in my contact list (employees of Comcast) and I have always been able to e-mail them in the past.  Also, I have another server with another provider that can communicate to both comcast.net and comcast.com mail servers:

 

$ host -t mx comcast.com
comcast.com mail is handled by 5 mx10.comcast.com.
comcast.com mail is handled by 5 mx20.comcast.com.
comcast.com mail is handled by 5 mx30.comcast.com.
comcast.com mail is handled by 5 mx40.comcast.com.
comcast.com mail is handled by 5 mx60.comcast.com.
comcast.com mail is handled by 5 mx50.comcast.com.
$ telnet mx10.comcast.com 25
Trying 162.150.44.68...
Connected to mx10.comcast.com.
Escape character is '^]'.
220 copdcmhin01.cable.comcast.com ESMTP SMTP Gateway
quit
221 2.3.0 copdcmhin01.cable.comcast.com closing connection
Connection closed by foreign host.

 

It works just fine from outside Comcast's internal network from *some* servers.  So I am still curious why I have some servers that are blocked for no apparent reason and I don't have a way to figure that out or worse yet get it fixed.  Any help on getting this resolved would be greatly appreciated.

Official Employee

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521 Messages

3 y ago

I do recommend that you reach out to our security assurance teams. Their website address is https://internetsecurity.xfinity.com/help/report-abuse/. Or you can reach them by phone 

Business Hours: 6:00am - 2:00am EST, 7 days a week; Contact: 1-888-565-4329.

New Contributor

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1 Message

5 m ago

were you able to resolve this?  II called Comcast / Xfinity and they said Comcast.com doesn't even exists for email addresses.   I had to explain the support tech it does and that we communicate with an employee with comcast.com 

We have to use Gmail as they won't get emails from my domain.

Anyone has an idea?  Do we need send connectors for this?

Official Employee

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9 Messages

Hello. I am sorry to read you are having trouble sending emails to https://comca.st/3vshtHE domains. I would start by contacting our amazing Customer Security Assurance Team. They have back end tools to help find a solution to your email concerns. Here is the contact info you need Business Hours: 6:00am - 2:00am EST, 7 days a week; Contact: 1-888-565-4329.