Connectivity and managing Your Comcast Business network
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Email Rejected By AOL, Others

OK, I purchased Comcast Business Internet so that I could put up my own server here in my basement at my home. So now the server is basically running and I'm migrating 54 domain names from my old server in the cloud to this new server (which should be a lot cheaper).  But I'm running into email issues.  I sent an email to a friend on AOL and I got this:


<*******>: host[] said: 521 5.2.1 :
(CON:B1) (in
reply to end of DATA command)


So, it is my guess (and it is entirely a guess) that AOL thinks my IP address from Comcast Business Internet is actually a home network and so it is refusing to accept email from my server.


So, one way to solve this would be to set up my server to relay through a Comcast email server of some sort.  I do have an alternative path (through Google), but that would cost me a LOT OF MONEY so I will not be happy if that is my only option.


So I'm asking you here what I can do to get around the wide IP block that AOL has up on IP addresses in my IP range (which is, if you need it, X.X.X.48/29).  Can you please help?

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Community Manager
Community Manager

Re: Email Rejected By AOL, Others

Welcome elbonian2.  A valid reverse DNS entry is required in order to validate the originating senders Mail Server and IP address.


Thank You

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New Contributor

Re: Email Rejected By AOL, Others

If you run your own DNS servers, you can ask that comcast deligate your reverse DNS entries to your servers which is something I had done last year.    Slightly less complicated and easier for the comcast support to do is have them create a PTR record for your email server's host name on the IP address that it lives on.


Re: Email Rejected By AOL, Others



You put in the valid reverse DNS entry for me before I even got the server built based upon an earlier forum post made under my other forum user name (before I came to understand that I was in the wrong user account when I was first posting here on the forum).



Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.






The email rejection by AOL has nothing to do with reverse DNS unless it is refusing to accept from which makes no sense at all.


I remain convinced that the IP address range you put my server into is being blocked by AOL on the grounds that it is a blok of home IP addresses, and I can't get around that issue by establishing reverse DNS.


Please do as I requested and have somebody from your email team respond to this thread.  IT IS NOT A REVERSE DNS ISSUE!!  I checked and reverse DNS is working just fine, thank you very much.....


== Bill


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Re: Email Rejected By AOL, Others



I got one of these a few weeks ago (not for Comcast, but my outgoing ISP). For some reason the link in the rejection notice doesn't work anymore (it did before), but try visting the AOL Postmaster support request site:


and select "Other Issues" from the dropdown box below the "For Internet Senders (non-AOL members)" section.


Next, select the "CON:B1" error message from the subsequent dropdown box.


Finally, fill out their stupid form to open a support request to try to get your IP off their blacklist.


I personally hate having to do this web form nonsense, but it seems to be standard practice among large mail providers.


The incident I mentioned above was for an IP address that I had for nine years(!); never sent bulk email, never had my server owned and used as a spam source -- just couldn't email AOL users anymore one day (and I could only a few months prior). Me thinks maybe AOL's filtering is now operating under a "guilty until proven innocent" mode.