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Mail Delivery Retention

    Question

  • Hi everyone,

    If you can help me on these question I appreciate.

    My question is, I have an environment with 1 CAS Server and 2 MBX Servers (Exchange 2013).

    My MX entry is pointing right to my CAS Server.

    If my 2 MBX servers are turned off for about 2 (two) hours. The emails sent to may Organization will be lost, right?

    -------

    My question is, I have an environment with 1 Hub Transport Server Server and 2 CAS/MBX Servers (Exchange 2010).

    My MX entry is pointing right to my CAS Server.

    If my 2 CAS/MBX servers are turned off for about 2 (two) hours. The emails sent to may Organization will be lost, right?

    Thank you in advance

    Luiz

    Monday, July 4, 2016 6:21 PM

Answers

  • >>> If my 2 MBX servers are turned off for about 2 (two) hours. The emails sent to may Organization will be lost, right?

    Now I've learned that the server should respond with this:

    451 4.7.0 Temporary server error. Please try again later. PRX3

    A 4xx error is a temporary (transient) error, and properly configured SMTP hosts should wait a while and retry the message up to its configured timeout period, which is typically one or two days.

    Having said all of that, your architecture isn't redundant.  I'd recommend that you add the CAS role to your two mailbox servers and then add a load balancer between them so you have redundancy in the CAS role.  Then you could remove the standalone CAS server.  Combined CAS and Mailbox roles is Microsoft's Preferred Architecture.


    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."
    Celebrating 20 years of providing Exchange peer support!





    Tuesday, July 5, 2016 5:42 AM
    Moderator
  • Corrected post above with a better story for you.

    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."
    Celebrating 20 years of providing Exchange peer support!


    Tuesday, July 5, 2016 7:03 AM
    Moderator
  • Agree with Ed. Microsoft preferred architecture is to have a multi server role. You need to have multi server load balanced with a HLB. Thanks.

    Regards, Riaz Javed Butt | Consultant Microsoft | mstechtalk.com

    Tuesday, July 5, 2016 7:15 AM

All replies

  • >>> If my 2 MBX servers are turned off for about 2 (two) hours. The emails sent to may Organization will be lost, right?

    Now I've learned that the server should respond with this:

    451 4.7.0 Temporary server error. Please try again later. PRX3

    A 4xx error is a temporary (transient) error, and properly configured SMTP hosts should wait a while and retry the message up to its configured timeout period, which is typically one or two days.

    Having said all of that, your architecture isn't redundant.  I'd recommend that you add the CAS role to your two mailbox servers and then add a load balancer between them so you have redundancy in the CAS role.  Then you could remove the standalone CAS server.  Combined CAS and Mailbox roles is Microsoft's Preferred Architecture.


    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."
    Celebrating 20 years of providing Exchange peer support!





    Tuesday, July 5, 2016 5:42 AM
    Moderator
  • Corrected post above with a better story for you.

    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."
    Celebrating 20 years of providing Exchange peer support!


    Tuesday, July 5, 2016 7:03 AM
    Moderator
  • Agree with Ed. Microsoft preferred architecture is to have a multi server role. You need to have multi server load balanced with a HLB. Thanks.

    Regards, Riaz Javed Butt | Consultant Microsoft | mstechtalk.com

    Tuesday, July 5, 2016 7:15 AM
  • Hi Ed,

    thank you for the help.

    Best Regards.

    Luiz

    Tuesday, July 5, 2016 11:12 AM
  • You're welcome.  Happy to have helped.

    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."
    Celebrating 20 years of providing Exchange peer support!

    Tuesday, July 5, 2016 6:39 PM
    Moderator
  • Hi,

    As Ed said, your architecture isn't redundant.

    You can use a Load balancer and DAG to configure high availability for Exchange 2013 Client Access servers and databases hosted on the Mailbox servers.

    Just add some related articles for your reference.

    https://technet.microsoft.com/en-us/library/jj898588(v=exchg.150).aspx

    https://technet.microsoft.com/en-us/library/dd979799(v=exchg.150).aspx

    Regards                                                                            

    David



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    David Wang_
    TechNet Community Support

    Wednesday, July 6, 2016 2:32 AM
    Moderator