Emails bouncing from comcast

captainron19

Active Member
Nov 10, 2011
33
1
56
cPanel Access Level
Root Administrator
A few days ago I was told by several people with sites on my VPS that emails were getting kicked back as undeliverable to comcast.net I co fumed this by trying to send an email also from server to a Comcast address I have and it was almost instant that it was kicked back with the message

“ all hosts for 'comcast.net' have been failing for a long time (and retry time not reached)”.

I tried one fix that I saw online pertaining to the exim (forget what the exact command lines were) but I ran them and restarted the exim and still happening . I also double checked and did not find my VPS’ IP blacklisted anywhere. I tried tech support with my server company and it has been days and they still do not know what is causing it.

I tried again today but now receiving a different reason in the kicked back email which is saying ...

Code:
“   host mx1.comcast.net 96.114.157.80
   SMTP error from remote mail server after initial connection:
   554 resimta-po-16v.sys.comcast.netresimta-po-16v.sys.comcast.net <ipRemoved> found on one or more DNSBLs, see postmaster.comcast.net/smtp-error-codes.php#BL000010 Postmaster : SMTP Error Codes”
Which to me the above means I am on a blacklist. I contacted the postmaster at Comcast and requested to be removed from their blacklist and they sent me an email last night assuring me that my IP address is not on their blacklist
 
Last edited by a moderator:

cPanelLauren

Product Owner
Staff member
Nov 14, 2017
13,295
1,273
313
Houston
Hello,


That error message from Comcast most definitely indicates that the block is due to being on a DNSBL:

Code:
<IPREMOVED> found on one or more DNSBLs, see postmaster.comcast.net/smtp-error-codes.php#BL000010 Postmaster : SMTP Error Codes
It may not be on a DNSBL currently but that is the reason for the bounce.


In general, it's good to follow the guidelines listed here

How to Keep your Email Out of the Spam Folder - cPanel Knowledge Base - cPanel Documentation

and if you have implemented all the suggestions I would suggest contacting Comcast again to ensure that your IP is removed from their filtering.


Thanks!
 

captainron19

Active Member
Nov 10, 2011
33
1
56
cPanel Access Level
Root Administrator
Hello,


That error message from Comcast most definitely indicates that the block is due to being on a DNSBL:

Code:
<IPREMOVED> found on one or more DNSBLs, see postmaster.comcast.net/smtp-error-codes.php#BL000010 Postmaster : SMTP Error Codes
It may not be on a DNSBL currently but that is the reason for the bounce.


In general, it's good to follow the guidelines listed here

How to Keep your Email Out of the Spam Folder - cPanel Knowledge Base - cPanel Documentation

and if you have implemented all the suggestions I would suggest contacting Comcast again to ensure that your IP is removed from their filtering.


Thanks!

I received a mesage back from comcast and was assured that we are not on their blacklist. My server company says that it is most likely a RDNS issue and tey were looking in to it but that was 3 days ago
 

cPanelLauren

Product Owner
Staff member
Nov 14, 2017
13,295
1,273
313
Houston
You would not have received that error message (which originates from the remote server) if they did not block you for that reason. If you're no longer on a blacklist or if they don't have you on one you shouldn't be continuing it experience issues sending mail to them. This issue is not something that cPanel has any control over, this is something your provider needs to assist you with.