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Some Emails do not get delivered

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  • Some Emails do not get delivered


    Originally when we installed our SBS 2003 I used a none registered domain “e.g. george.local” to configure the server. The exchange server just used to send emails between the office employees (around 15 people all together).

    Later on it was decided that we buy our own domain and open up our exchange server to send and receive the emails to/from outside our network. I used the “How do I configure my Exchange 2000/2003 server to accept e-mails for domains other than my own?” from this site to add the registered domain “e.g.” to the SMTP under Exchange.

    Since then everything is working great and almost 98% off emails initiated from our network is delivered successfully. For other 2% I get the following error when the email is sent under [email protected]:

    “There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.
    <server.GEORGE.local #5.5.0 smtp;550- blocked by ldapu=rblmx,dc=att,dc=net>”

    I assume this error cause by the recipient server checking to see if the sending server has the same domain as sender to prevent SPAM.

    My question is: how can I fix this problem? I was thinking to use “domainrename” utility to change the server domain. But I am not sure if this is the right approach.

    I have only one server in my network
    Any help and advice is greatly appreciated.



  • #2
    Re: Some Emails do not get delivered

    Looks like AT&T are blocking the messages as potential spam.

    You don't seem to be blacklisted but this might help


    • #3
      Re: Some Emails do not get delivered

      Renaming the domain is not the solution.
      The WINDOWS domain has nothing to do with the EMAIL domain that you are using.

      As already pointed out, that error is unique to AT&T, if you are getting blacklisted elsewhere then you need to investigate why.
      However if your server is set to announce itself as host.domain.local then that can cause a problem.

      ESM, Servers, <your server>, Protocols, SMTP. Right click on the default SMTP VS and choose Properties. Click on the tab Delivery and then Advanced. Change the FQDN to match the MX record host name.

      If you are on a dynamic IP address or your email comes in via the POP3 connector then you should be using your ISPs SMTP Server as a smart host. Run the Internet and Email connection wizard to set the smart host.

      Simon Butler
      Exchange MVP

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      Sembee is a registered trademark, used here with permission.


      • #4
        Re: Some Emails do not get delivered

        Thank you Sembee and all.

        I change the FQDN on my server and also change the DNS for reverse look up and the problems has been resolved.

        Many thanks for your help and suggestions.