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Comcast Postmaster Page Live

Official Employee

Comcast Postmaster Page Live

I don't think I have seen formal mention of this yet, so FYI we now have a Comcast.Net Postmaster page live at http://postmaster.comcast.net.
 
The site features an area where news is highlighted, you can find links to our feedback look and RBL info, list of servers, best practices, and FAQs.  RSS feeds throughout for you to subscribe to updates.  This is just the first version, and we expect to continue to improve and enhance this page over time.
 
JL
JL
Internet Services


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Re: Comcast Postmaster Page Live

Bronze Problem Solver

Re: Comcast Postmaster Page Live



evie210 wrote:
2 very useful pages:
 
 

550 - [Invalid sender domain]  Comcast requires that all sending IPs have a valid A or MX record. This error results when neither record can be found.
 
  This doesn't make sense. It should say that Envelope Sender domains must have A or MX records, or something like that.
Service Expert

Re: Comcast Postmaster Page Live



jlivingood wrote:
I don't think I have seen formal mention of this yet, so FYI we now have a Comcast.Net Postmaster page live at http://postmaster.comcast.net.
 
The site features an area where news is highlighted, you can find links to our feedback look and RBL info, list of servers, best practices, and FAQs.  RSS feeds throughout for you to subscribe to updates.  This is just the first version, and we expect to continue to improve and enhance this page over time.
 
JL



  • Watch the sending limits

    Comcast allows 2 simultaneous connections per sending IP address.
    Comcast allows 1000 recipients per message.
    Comcast allows a throttle rate based on your sender reputation and authentication.


Is this a typo or did something change?  I thought the limit was 100?  Is SmartZone going to allow more recipients?



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Re: Comcast Postmaster Page Live



Again wrote:


jlivingood wrote:
I don't think I have seen formal mention of this yet, so FYI we now have a Comcast.Net Postmaster page live at http://postmaster.comcast.net.
 
The site features an area where news is highlighted, you can find links to our feedback look and RBL info, list of servers, best practices, and FAQs.  RSS feeds throughout for you to subscribe to updates.  This is just the first version, and we expect to continue to improve and enhance this page over time.
 
JL



  • Watch the sending limits

    Comcast allows 2 simultaneous connections per sending IP address.
    Comcast allows 1000 recipients per message.
    Comcast allows a throttle rate based on your sender reputation and authentication.


Is this a typo or did something change?  I thought the limit was 100?  Is SmartZone going to allow more recipients?


  That stuff is for incoming email, not for outgoing through smtp.comcast.net.
Service Expert

Re: Comcast Postmaster Page Live

What "stuff", Steve?  That particular entry pertains to sending and says, "Watch the sending limits".

My question is, there is currently a sending limit of 100 recipients per email.  On the new Postmaster page is that a typo or has something recently changed?  When SmartZone is released, is the sending limit being upped to 1000 recipients or will it still be at 100?

Or, did I miss something in your reply that you thought was obvious?




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Bronze Problem Solver

Re: Comcast Postmaster Page Live

Steve is right, it's inbound.

Remember the postmaster page is more oriented to others trying to connect to us than our customers trying to send out, so when we refer to 'sending limits' we mean those people sending to us from external sources.


Service Expert

Re: Comcast Postmaster Page Live

Thanks for the clarification, Chris.

Postmaster pages I've visited in the past, however, have been for both inbound and outbound.



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Bronze Problem Solver

Re: Comcast Postmaster Page Live



steve-baker wrote:


evie210 wrote:
2 very useful pages:
 
 

550 - [Invalid sender domain]  Comcast requires that all sending IPs have a valid A or MX record. This error results when neither record can be found.
 
  This doesn't make sense. It should say that Envelope Sender domains must have A or MX records, or something like that.


  No comment from Comcast? "IPs" never have A or MX records, you guys look like silly buggers saying something like that.
 
  Also:
 
"554 - [<IP>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. For more information, refer to: http://www.comcast.net/help/faq/index.jsp?faq=SecurityMail_Policy18784]  Comcast requires all sending IP addresses have a valid rDNS. This error results when no entry is found."
 
  Isn't quite right, although I could be nitpicking. "when no entry is found" doesn't exactly mean that a PTR record doesn't exist, "no entry is found" when there are temporary errors, too. Should be more like "when there is no PTR record".
 
 Also:
 
"Prior to sending an email message with a large attachment, please be sure that the recipient can accept the message. If your message is larger than the recipient's email box size limit, the message will be rejected. With your Comcast e-mail accounts, the e-mail attachment file size limit is 15MB. "
 
  That's very misleading, it says that you could attach a 14 MB binary file. You can't, the encoding would take it over 15 MB, and Comcast wouldn't accept it.
Official Employee

Re: Comcast Postmaster Page Live

Steve,
No question that your first comment is true in the technical sense.  To be fair, that error message has been in use for probably in excess of 5 years and everyone has understood it's intent.  Not a bad idea to make it more technically correct though.
To your second point, I think the distinction you're making is "query failed" vs. "query succeed and nothing was found."  These are two different situations that cause two different errors.  Query failed is (or could be) a temporary situation and results in a 4xx temp-fail error.  The error you commented on is when the query succeeds and nothing was found - a 5xx level error.
With your last point, that's a fair point and worth correcting to make more accurate.  We'll look at correcting that.



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New Poster

Re: Comcast Postmaster Page Live

I am using IIS SMTP and I can not send any email to comcast.net 

I am not the blacklist or blockedlist. Is there any guide to help me setup my SMTP to compatible with Comcast. I dont have any issue sending email to other domain. Just comcast. It's very annoying.

 

 

 

Connection Expert
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Re: Comcast Postmaster Page Live