Unable to send mail through Exhcange server 2K!!!

Posted on 2005-04-21
Last Modified: 2010-04-10

My test network at home consists of a XP workstation, 2003 Domain Controller and Exchange Server.  I have communication  between all 3 machines.  I'm able to receive domain mail and my POP3 mail but I'm unable to send any mail.

 I'm trying to send my mail "through" my Exchange server rather than directly to my ISP, thus the "test network".

This is the latest error message I got when I tried sending to a yahoo email.

The message cannot be delivered due to a configuration error on the server. Please contact your Administrator.
  <exchangeserver.Babylon.local #5.3.0 smtp;553 5.3.0 flpvm21,DNSBL:

I get this or a similiar error no matter where I try to email too.  If I send directly from the workstation to my ISP, no problem.

Any suggestions??............

thanks in advance....

Question by:cyoung3000

    Expert Comment

    Couple of things to check.

    DNSBL is a blacklist of domain names.  You should do a google search on DNSBL and make sure that your domain is not blacklisted.

    Your ISP might block port 25, call them and find out, you might be able to get that open.  Also you might want to forward email thru your isp, instead of using DNS, that can be found under the properties of the SMTP COnnector

    Make sure relay is not enabled also
    LVL 79

    Expert Comment

    Check your DNS configuration. Do you have a proper MX record in the proper public domain for your mail server?

    LVL 3

    Expert Comment

    Your server is trying relay message, which most ISP don't allowed

    lrmoore -> Do you have a proper MX record in the proper public domain for your mail server?

    LVL 10

    Expert Comment

    I have the same setup... the solution that is working for me (for how long I often wonder) is to use the ISP's SMTP server as a 'smart host' for outbound email on the Exchange server.  Most of the dynamic IP blocks assigned by large service providers are identified as such by spam filtering products and are summarily blocked.
    LVL 10

    Expert Comment

    Well, ruddg has a good suggestion, my other concern though is if your Exchange server is setup to act as an "Open Relay" as xrok discussed. Really, you need to check to make sure you are actually authenticating users who attempt to use SMTP that are not on your local subnet. You would have had to actually configure it to make it an Open Relay but I have seen administratos have problems sending mail and decide to just convert their mail server into an Open Relay to fix the problem. Its like getting rid of all the doors and windows in your house because you locked yourself out one day.
    LVL 4

    Expert Comment

    Can you send through your exchange to yourself? Or the problem occurs only when you trying to send something out of your net?

    Author Comment

    I'm unable to send out of my network.  I'm also able to receive all email, no problem.
    LVL 10

    Accepted Solution

    cyoung3000, have you tried using your ISP SMTP server as a smart host?

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