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Exchange Server 2007

    Question

  • Hello, I am running Exchange Server 2007... I am planning on upgrading soon but for now I have to continue to use this version.  I have a problem where i can send and receive to and from all but 1 or 2 domains.  For example, I send to one particular domain and I get a delayed message and the message stays in my outgoing queue.  The error is 451 4.4.0 Primary target IP address responded with: "421 421.4.2.1 Unable to connect." Attempted Failover to alternate host, but that did not succeed....

    I don't send out via a filter, just a firewall NAT and static IP.  The server has been running well including sending to these  domains that have the problem this month but I can't figure out why all of a sudden I'm getting this error and unable to send to certain domains.  I can receive email from these domains but for a select few they won't deliver.  I have run a "Test email server" on MXToolbox and all comes back ok except for my SMTP transaction time.  I've seen a lot of similar questions in the forums and have checked everything and all looks OK.  This is a problem for us since we need to work with certain companies.  Any help would be greatly appreciated!  

    Thank you!


    CM

    Tuesday, June 05, 2018 7:24 PM

All replies

  • Many folks would consider it negligent to be running an email server that is 11 years old, and no longer able to receive modern security patches. There is no excuse for exposing your users to unsafe systems.

    Having said that, it sounds like you may be on a black list. MXtoolbox has a blacklist checker for your IP address. You can also try to test connectivity directly from the server's command prompt. If not a blacklist, you're dealing with a connectivity issue. Here is an article that discusses this type of troubleshooting: https://technet.microsoft.com/en-us/library/bb123686(v=exchg.160).aspx


    Mike Crowley | MVP
    My Blog -- Baseline Technologies

    Thursday, June 14, 2018 10:30 PM