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There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.

    Question

  • There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.
      <" Server FQDN" #5.5.0 smtp;550-5.7.1 [server ip 1] Our system has detected an unusual rate of>
    Friday, April 29, 2011 2:24 PM

Answers

  • There was a SMTP communication problem with the recipient's email
    server. Please contact your system administrator.   <" Server FQDN"
    #5.5.0 smtp;550-5.7.1 [server ip 1] Our system has detected an unusual
    rate of>

    Given that the message was truncated, all I can do is suppose what was
    the remainder of the message, that is "an unusual rate of connections
    from
    your IP" which means that your server is really bashing the destination
    one
    now; if your exchange is configured to perform direct delivery (no
    smarthost)
    you'd better ensure there's no compromised machine sitting inside your
    network and pumping out spam through it; otherwise. if you're using some
    smarthost for email delivery, you should contact whoever administers
    that
    server and report the issue; also notice that the issue may be caused if
    you aren't using a smarthost and if the IP used by your exchange to go
    out
    to the internet is also used for "web surfing" from your network; in
    such a
    case, some infected machine(s) sitting on your LAN may be pumping out
    "direct-to-MX" junk w/o even going through your exchange but the
    source
    IP would be the same; in such a case ensure to BLOCK outbound access
    to port 25/tcp for all hosts except your exchange server which should be
    the only one allowed to deliver SMTP email for your organization

    • Marked as answer by Gavin-Zhang Friday, May 06, 2011 8:05 AM
    Friday, April 29, 2011 3:40 PM
  • Hi Zeratul300,

    Could you please post more information about the issue?
    What about the exchange server and outlook version?
    How many users have the issue, or just one, or the issue just occured the emails send to some special recipients?
    1. Above gave some good suggestion, please also confirm the recipients email address were typed correctly; Such as: not using single quote sign.
    2. Use the http://www.mxtoolbox.com/ to check you public ip whether is listed in the blacklist
    3. Check that do yo configure a external DNS server in the smtp virtual server, if so, please remove it and make some tests

    Regards!
    Gavin


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.
    • Marked as answer by Gavin-Zhang Friday, May 06, 2011 8:05 AM
    Tuesday, May 03, 2011 8:33 AM

All replies

  • There was a SMTP communication problem with the recipient's email
    server. Please contact your system administrator.   <" Server FQDN"
    #5.5.0 smtp;550-5.7.1 [server ip 1] Our system has detected an unusual
    rate of>

    Given that the message was truncated, all I can do is suppose what was
    the remainder of the message, that is "an unusual rate of connections
    from
    your IP" which means that your server is really bashing the destination
    one
    now; if your exchange is configured to perform direct delivery (no
    smarthost)
    you'd better ensure there's no compromised machine sitting inside your
    network and pumping out spam through it; otherwise. if you're using some
    smarthost for email delivery, you should contact whoever administers
    that
    server and report the issue; also notice that the issue may be caused if
    you aren't using a smarthost and if the IP used by your exchange to go
    out
    to the internet is also used for "web surfing" from your network; in
    such a
    case, some infected machine(s) sitting on your LAN may be pumping out
    "direct-to-MX" junk w/o even going through your exchange but the
    source
    IP would be the same; in such a case ensure to BLOCK outbound access
    to port 25/tcp for all hosts except your exchange server which should be
    the only one allowed to deliver SMTP email for your organization

    • Marked as answer by Gavin-Zhang Friday, May 06, 2011 8:05 AM
    Friday, April 29, 2011 3:40 PM
  • Hi Zeratul300,

    Could you please post more information about the issue?
    What about the exchange server and outlook version?
    How many users have the issue, or just one, or the issue just occured the emails send to some special recipients?
    1. Above gave some good suggestion, please also confirm the recipients email address were typed correctly; Such as: not using single quote sign.
    2. Use the http://www.mxtoolbox.com/ to check you public ip whether is listed in the blacklist
    3. Check that do yo configure a external DNS server in the smtp virtual server, if so, please remove it and make some tests

    Regards!
    Gavin


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.
    • Marked as answer by Gavin-Zhang Friday, May 06, 2011 8:05 AM
    Tuesday, May 03, 2011 8:33 AM