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How to Stop the ESMTP Verb in Exchange 2007 RRS feed

  • Question

  • Dear All,

    I am having two AD sites which contains separate Hub/cas server and mailbox server, recently we changed Cisco PIX to CISCO ASA,  hub servers not communicate with each others even after I disabled ESMTP inspection in the ASA.

    If there is any way to disable ESMTP in Exchange 2007???? for Exchange Hub to Hub communication or entire server.

    I found MS KB for how to disable ESMTP in Exchange 2000/2003 not for Exchange 2007.

    Please Help

    Cheers
    AFRAZ
    Monday, March 30, 2009 2:29 PM

Answers

  • No you cannot disable ESMTP for intra-organization (Exchange server to Exchange server) connectors.  You can only do this on outbound connections, e.g. set-sendconnector <id> -ForceHELO:$true.

    But SMTP is not the communication used between Hub/cas and mailbox.  It uses Exchange RPC (essentially MAPI).  Putting a firewall between Hub/cas and mailbox roles is not supported.

    -Scott
    • Marked as answer by Elvis Wei Tuesday, April 7, 2009 6:39 AM
    Monday, March 30, 2009 2:53 PM
  • Hi Afraz,

    As Scott said above, it cannot be modified.

    Between hub transport servers, it use SMTP TLS for communication. There is a implicit connector that is automatically computed based on the system topology, it can’t be modified. Could you let us know why you need to disable ESMTP in firewall?

    Thanks,

    Elvis

    • Marked as answer by Elvis Wei Tuesday, April 7, 2009 6:39 AM
    Wednesday, April 1, 2009 8:13 AM

All replies

  • No you cannot disable ESMTP for intra-organization (Exchange server to Exchange server) connectors.  You can only do this on outbound connections, e.g. set-sendconnector <id> -ForceHELO:$true.

    But SMTP is not the communication used between Hub/cas and mailbox.  It uses Exchange RPC (essentially MAPI).  Putting a firewall between Hub/cas and mailbox roles is not supported.

    -Scott
    • Marked as answer by Elvis Wei Tuesday, April 7, 2009 6:39 AM
    Monday, March 30, 2009 2:53 PM
  • ESMTP has pretty much become the standard for email relay throughout the world.  I see very few mailservers that cannot talk it... it also uses the same port 25 as standard SMTP.  If you enable SMTP logging you will be able to view that pretty much all your mail comes in through ESMTP from the internet.

    How does a server know wheather to use SMTP or ESMTP?
    Servers initiate a EHLO request when sending an email... if the other server replys it uses ESMTP.  If the server doesnt reply and is like "what???" it issues a standard HELO request, which then initates standard SMTP.

    In regards to your mail not relaying between sites... are there any errors your recieving on your exchange hub transport servers?  Can you please paste them here.
    Clint Boessen MCSE, MCITP: Messaging

    L7 Solutions, Microsoft Gold Partner
    Perth, Western Australia
    Tuesday, March 31, 2009 2:40 AM
  • Hi Afraz,

    As Scott said above, it cannot be modified.

    Between hub transport servers, it use SMTP TLS for communication. There is a implicit connector that is automatically computed based on the system topology, it can’t be modified. Could you let us know why you need to disable ESMTP in firewall?

    Thanks,

    Elvis

    • Marked as answer by Elvis Wei Tuesday, April 7, 2009 6:39 AM
    Wednesday, April 1, 2009 8:13 AM