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Does outlook disconnects the connection from Exchange server once emails are retrieved and cached locally? RRS feed

  • Question

  • Does outlook disconnects the connection from Exchange server once emails are retrieved and cached locally OR it is always connected to Exchange server? 

    I am trying to understand this: I heard outlook syncs with Exchange server for every 15 seconds. if outlook is always connected to Exchange server why it takes 15 seconds to sync.

    Could you please help to understand this? 


    • Edited by kartheen Friday, December 20, 2019 5:41 AM
    Friday, December 20, 2019 5:31 AM

Answers

  • Hi Kartheen,

    If you are using an Exchange account on your Outlook client, there are two modes available: Exchange Cached mode and Online mode.

    By defaut, your Outlook is started in Cached mode. In this mode, a copy of your mailbox is saved on your computer, what you are looking at is a local cache(OST) instead of directly at your mailbox on the Exchange server. Outlook will download the messages after they have arrived Exchange server for 30 seconds. These 30 seconds are used by the Exchange server to process mail (scanning and server-side policies).

    Then if you have make a change in local Outlook client, that change is synced to your Exchange server after 15 seconds.

    Of course if you start your Outlook client in Online mode, you are looking at your mailbox directly on your Exchange server, all changes will be synced immediately. However, this can casue freezing since Outlook has to constantly connect to our servers.

    For your reference: 

    Turn on Cached Exchange Mode.

    Sync interval for Exchange account.

    Hope the information above can help you understand this better.

    Regards,

    Aidan Wang


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    Friday, December 20, 2019 7:23 AM
  • Hello Hari, 

    Thank you so much. 

    what I am trying to understand when I send email from pop3 or IMAP using outlook application, it submits the message to Exchange server, it can also be encrypted using SSL. But when I send an email from outlook using MAPI, does it submit the message to exchange server or it syncs the message  from local OST cache file to server mailbox?  Can you please help to clarify?

    THe message is submitted to the Exchange Server. The message is then sycned from your mailbox Outbox to your .ost client outbox folder. 
    • Edited by Andy DavidMVP Tuesday, January 7, 2020 4:08 PM
    • Marked as answer by kartheen Tuesday, January 7, 2020 4:33 PM
    Tuesday, January 7, 2020 4:06 PM
  • It is submitted to Exchange server not from cache to exchange server.
    • Marked as answer by kartheen Tuesday, January 7, 2020 4:34 PM
    Tuesday, January 7, 2020 4:08 PM
  • Awesome! Thanks for your answer Andi. Could you please tell me which protocol used to submit the message from Outlook to Exchange server? Is it MAPI over HTTPS? 

    MAPI would be it.
    • Marked as answer by kartheen Wednesday, January 8, 2020 2:47 PM
    Tuesday, January 7, 2020 11:09 PM

All replies

  • Hi Kartheen,

    If you are using an Exchange account on your Outlook client, there are two modes available: Exchange Cached mode and Online mode.

    By defaut, your Outlook is started in Cached mode. In this mode, a copy of your mailbox is saved on your computer, what you are looking at is a local cache(OST) instead of directly at your mailbox on the Exchange server. Outlook will download the messages after they have arrived Exchange server for 30 seconds. These 30 seconds are used by the Exchange server to process mail (scanning and server-side policies).

    Then if you have make a change in local Outlook client, that change is synced to your Exchange server after 15 seconds.

    Of course if you start your Outlook client in Online mode, you are looking at your mailbox directly on your Exchange server, all changes will be synced immediately. However, this can casue freezing since Outlook has to constantly connect to our servers.

    For your reference: 

    Turn on Cached Exchange Mode.

    Sync interval for Exchange account.

    Hope the information above can help you understand this better.

    Regards,

    Aidan Wang


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    Friday, December 20, 2019 7:23 AM
  • Hi,

    Have you got the issue fixed?

    I'm writing to see if the reply above is helpful to you. If yes, would you mind helping mark the reply as answer? So that others who might have a similar question can benefit from your thread? Thanks for your understanding and support.

    Regards, 

    Aidan Wang


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.


    Monday, December 23, 2019 8:32 AM
  • Hello Aidan,

    Thanks a lot for your answer. I got a better understanding now with your answer. I have one more question if you can help.

    when i send an email from my outlook, does my outlook submit the message to exchange server? if so, using which protocol? 

    Or

    Does it sync my sent email to exchange server? If so, with what mechanism it syncs? 

     

    Tuesday, January 7, 2020 2:36 PM
  • TO be precise outlook though it is in cache mode it will be in sync with exchange server so there wont be any much difference if you notice the time taken when the outlook is in cache mode or in online mode..You can try with a test email and the time it takes to get that email in OWA as well as in cache mode.. but the main difference would be the ost size (local cache) as adian mentioned.
    Tuesday, January 7, 2020 2:49 PM
  • Yes it would and the protocol  would be MAPI to connect with clients.

    MAPI is a microsoft protocol which allows client to fully utilize the features of an exchange server including emails, address book, calendars and public folders where MAPI uses RPC based communication.

    https://www.contactgenie.info/understanding-email-protocols-pop-imap-mapi-eas/ would help you in better way

    [If a post helps to resolve your issue, please click the "Mark as Answer" of that post or click Answered"Vote as helpful" button of that post. By marking a post as Answered or Helpful, you help others find the answer faster. ]


    Tuesday, January 7, 2020 2:55 PM
  • Hello Hari, 

    Thank you so much. 

    what I am trying to understand when I send email from pop3 or IMAP using outlook application, it submits the message to Exchange server, it can also be encrypted using SSL. But when I send an email from outlook using MAPI, does it submit the message to exchange server or it syncs the message  from local OST cache file to server mailbox?  Can you please help to clarify?

    Tuesday, January 7, 2020 3:53 PM
  • Hello Hari, 

    Thank you so much. 

    what I am trying to understand when I send email from pop3 or IMAP using outlook application, it submits the message to Exchange server, it can also be encrypted using SSL. But when I send an email from outlook using MAPI, does it submit the message to exchange server or it syncs the message  from local OST cache file to server mailbox?  Can you please help to clarify?

    THe message is submitted to the Exchange Server. The message is then sycned from your mailbox Outbox to your .ost client outbox folder. 
    • Edited by Andy DavidMVP Tuesday, January 7, 2020 4:08 PM
    • Marked as answer by kartheen Tuesday, January 7, 2020 4:33 PM
    Tuesday, January 7, 2020 4:06 PM
  • It is submitted to Exchange server not from cache to exchange server.
    • Marked as answer by kartheen Tuesday, January 7, 2020 4:34 PM
    Tuesday, January 7, 2020 4:08 PM
  • Awesome! Thanks for your answer Andi. Could you please tell me which protocol used to submit the message from Outlook to Exchange server? Is it MAPI over HTTPS? 

    Tuesday, January 7, 2020 4:36 PM
  • Thanks for your answer Hari. Could you please tell me which protocol used to submit the message from Outlook to Exchange server? Is it MAPI over HTTPS? 
    Tuesday, January 7, 2020 6:45 PM
  • Awesome! Thanks for your answer Andi. Could you please tell me which protocol used to submit the message from Outlook to Exchange server? Is it MAPI over HTTPS? 

    MAPI would be it.
    • Marked as answer by kartheen Wednesday, January 8, 2020 2:47 PM
    Tuesday, January 7, 2020 11:09 PM