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Email being blocked from Yahoo.com and SBCGlobal.net

I have a client that has an opt-in email list. His emails are being blocked when sending to sbcglobal.net and it seems like yahoo.com is throttling emails to their addresses. Anyone have experience in this situation? We've already tried emailing them to take us off their blacklist (if we're on them), setting up RDNS, SPF Records, installing Domain Keys, new IP address. What else is there?

What can we do to troubleshoot?
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victornegri
Asked:
victornegri
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1 Solution
 
Gideon7Commented:
Put the IP address of your client's mailserver into the SPAM RBL meta-checker at http://moensted.dk/spam/.  It will report how many different blacklists your client is on.
If you get many hits, it may be indication that your client's bulk mailings are not so "opt-in".
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victornegriAuthor Commented:
The domain and/or IP are not being blocked by any of the RBLs.
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moorhouselondonCommented:
Use DNSReport or similar tool to find out whether the email server and domain you are sending out from is properly configured e.g., reverse DNS is setup.

www.dnsstuff.com
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moorhouselondonCommented:
Sorry, I reread the Q and see you've already checked RDNS.  DNSStuff also has an RBL checker which checks your details against a range of RBL sites.
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victornegriAuthor Commented:
DNSStuff says that the domain is in 0 blacklists.
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moorhouselondonCommented:
What package is being used to send these emails?  Many emailer programs have a unique "signature" which is evident in the headers of the received email.  If these were being checked by the incoming mail server this might be a reason for their being blocked.  What happens if this user sends out individual emails to these domains?  Do they get received ok?  (I know this is not a solution, but we need to diagnose where the problem lies).
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victornegriAuthor Commented:
Single emails to our test addresses at yahoo.com seem to go through fine. Single emails to sbcglobal.net generate the following NDR (which looks like we're on an sbc blacklist):

The following recipient(s) could not be reached:

      user@sbcglobal.net on 3/10/2009 7:28 PM
            The destination system is currently not accepting any messages.  Please retry at a later time.  If that fails, contact your system administrator.

            <ourmailserver.ourdomain.com #5.3.0 smtp;553 5.3.0 flpi184 - n2B2Qd6C018105, DNSBL:ATTRBL 521< 1.2.3.4 >_is_blocked.__For_information_see_http://att.net/blocks>
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victornegriAuthor Commented:
Will find out what mail package we use. I want to say it's just a Microsoft Access function sending emails to our Exchange server to be forwarded to the recipients.
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victornegriAuthor Commented:
Found out: The package is called IDS Mail and it is an ocx for vb and access.

Also just did a check with http://www.mxtoolbox.com/blacklists.aspx and it shows we're on 0 blacklists.
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moorhouselondonCommented:
Looks like their diagnostic message needs to be updated.  Check this instead:-

http://worldnet.att.net/general-info/block_inquiry.html
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moorhouselondonCommented:
The fact that blocking is occurring even when using a regular mail client e.g., Outlook, means it is not the mailer that is causing the problem with AT&T.
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victornegriAuthor Commented:
I contacted SBC through their website and requested that we get removed from their blacklist and somehow that worked. As for Yahoo, we parsed all the NDRs we were getting (because there were some bogus email addresses on our email list from people who thought they would be funny). Now Yahoo seems to send faster. I guess they throttle based on if they see a lot of bad email addresses going into their system.

Thanks for sticking with me on this subject.
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