Community Forum

Comcast blocking AWS, Digital Ocean emails?

New Poster

Re: Comcast blocking AWS, Digital Ocean emails?

@CCAntiSpam  Thank you for getting mail flowing to comcast.net addresses from IP 45.55.238.90.  However, I'm seeing aggressive ratelimiting for any messages that happen to have 3 or more comcast.net recipients:

 

421 4.1.0 45.55.238.90 Throttled - try again later. Please see http://postmaster.comcast.net/smtp-error-codes.php#RL000001

 

Greylisting like this is understandable, however these messages seem to never deliver despite multiple attempts and eventually just fail and bounce back to the sender.  Simply lowering delivery retry timeout as suggested at http://postmaster.comcast.net/smtp-error-codes.php#RL000001 has no effect.  However, if I remove a recipient or 2 from such messages, so only 2 comcast.net recipients are on the message, it delivers fine.  Likewise messages with 1 or 2 recipients with comcast.net addresses always deliver fine.

 

The server at IP 45.55.238.90 is a private mailserver with very low traffic.  Messages with 3 or more comcast.net recipients are rare, but they do occur a couple times a month or so.  In short, these are private correspondences between small groups of friends that hit Reply All.

 

Is there any way you can ratelimit IP 45.55.238.90 less aggressively?  Maximum number of comcast.net recipients for messages from this IP really shouldn't exceed 4, and that only happens a couple times a month.

 

If there is anything you can do to help further it would be appreciated.

 

Bronze Problem Solver

Re: Comcast blocking AWS, Digital Ocean emails?

@natenate19 I'll take a closer look, it shouldn't be operating like that.  I've given you an override for a bit to try to help train the systems involved.  Let us know if you continue to see issues.


I am a Retired Official Comcast Employee and no longer actively support the Xfinity Forum.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark a post as the Best Answer!
New Poster

Re: Comcast blocking AWS, Digital Ocean emails?

@CCAntiSpam Thanks again for your assistance, I'll let you know if I happen to see any further issues.

 

New Poster

Re: Comcast blocking AWS, Digital Ocean emails?

@CCAntiSpam Same issue here for server on ip 52.55.38.169
Bronze Problem Solver

Re: Comcast blocking AWS, Digital Ocean emails?

@Timevex Please try again, let us know if the problem recurs.


I am a Retired Official Comcast Employee and no longer actively support the Xfinity Forum.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark a post as the Best Answer!
New Poster

Re: Comcast blocking AWS, Digital Ocean emails?

I'm having the same issue.  Where would I post my domains and email server IP that's secure?

Highlighted
New Poster

Re: Comcast blocking AWS, Digital Ocean emails?

@CCAntiSpam Mail server address is: 52.22.43.252

 

We can't send mail to any comcast addresses.

 

New Poster

Re: Comcast blocking AWS, Digital Ocean emails?

@CCAntiSpam : I'm having the same issue as well

 

IP Address: 162.243.142.118

Domain: toddles.com

 

Thanks