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derel's profile

New Member

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10 Messages

Monday, March 6th, 2023 11:43 PM

IPs listed on AT&T RBL

AT&T

We are both and AT&T and Comcast customer. Recently message from our MS Exchange server (which runs on the Comcast network) have been blocked by AT&T's RBL. We have tried different IPs, and it appears our entire block (75.144.45.224/29) is listed on this RBL. We have been forwarding countless NDRs to abuse_rbl@abuse-att.net and have heard nothing. This is affecting communication with our clients and would appreciate any assistance is resolving this issue.

Thanks,

David

ACE - Expert

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35.9K Messages

1 year ago

My recommendation:

1) Send no more than one e-mail every 3 or 4 days.  Collect multiple NDRs into one e-mail if you want to deliver the magnitude

2) Write an e-mail that looks like human business communication, not something a spam bot would generate/forward

3) in the e-mail,

  • discuss your history with the IP (or IP block), i.e. how long you've had it,
  • when you noticed an issue
  • any issues you've corrected that might have cause your IP block to be blocked.  {be aware, AT&T could have blocked something even larger than your /29 due to something done in by someone in an adjacent block).
  • aver your commitment to not sending SPAM through your connection (to AT&T's customers or anyone else).

5) Also ensure that your DKIM, SPIF, and PTR records are all in tip-top shape.  

6) Make sure your IP [block] is not on any public RBLs.

If your IP block is in a range also used for consumers, this could be part of your issue.  You may at the very least find you're listed on one of the RBL services' list of dynamic IPs for this reason.

(edited)

New Member

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10 Messages

1 year ago

Thanks for the comments Jeffer. Most of what you listed I have done, but I had not thought about the potential that a much larger range than our /29 had been blocked. We're clear of all public RBLs (as best I can tell) and all the usual suspects (SPF etc.) are all correct.

We'll try to remain patient and see if we can get a response from them.

New Member

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10 Messages

1 year ago

This is crazy. I cannot believe how many companies are in this same boat and getting no response from the abuse address. This is first began happening to us we have changed all of our services to AT&T and thus have a new IP block. Right off the bat, the exact same thing is occurring. the ATT RBL is blocking one of their own IPs. 

Does anyone have any tips on how to get a response. (Edited per community guidelines), even if it's only an explanation of what the real issue is it would be helpful.

(edited)

New Member

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7 Messages

1 year ago

@derel

Explicitly defining the steps taken to correct the issue seemed to get action for me (after 4 weeks of emailing the postmaster alias). I had a similar issue though. In my case, it looked like we were spoofing due to SPF not being updated for one of our sender domains after migrating into a new datacenter with a brand new PTR IP. Just saying I fixed SPF with a domain was not enough. Once I listed the steps taken to resolve and included our sender domains, the block was removed the next day. I did not get any correspondence other than the generated response. I had just been checking logs every day to see if it was unblocked.

Its not a transparent process at all. I feel your frustration. The fact youre a customer of ATT and you cant get this resolved since Mar6 is crazy!

New Member

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10 Messages

1 year ago

@brassring_engineer 

I'll keep that in mind. Our SPF record and RDNS are both OK. We currently don't use DKIM, but lack of this shouldn't be the issue. One of the AT&T folks on the forum reached out about this so I'm hopefully something will change soon. I'll keep in mind to be more detailed if I need to contact the abuse alias again.

Even more frustrating than this is that the IP block they assigned us is listed on SORB's dynamic host list. Any mail servers utilizing this reject the connection and report that the sending IP is from a dynamic pool. We've not even been using our AT&T service 10 days and these are the issues we start out with. Not a great start if you ask me. 

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