How Offline Address Book Works In Exchange 2007…

A clear understanding of how the offline address book works in exchange helps an admin in troubleshooting the related issues. This article explains how oab works in the 2007 edition. The Exchange System Attendant service is responsible for the generation of oab. This service is available only on a server that has the mailbox role…

A clear understanding of how the offline address book works in exchange helps an admin in troubleshooting the related issues. This article explains how oab works in the 2007 edition.

The Exchange System Attendant service is responsible for the generation of oab. This service is available only on a server that has the mailbox role installed. The SA invokes a dll file called oabgen.dll. To find out the server that is generating the offline address book, launch EMC –> Organizational Configuration –> Mailbox –> OAB tab.

Generation Server OAB

Once you have made too many changes in exchange, you can update the address book by right clicking and selecting Update. By default, oab is updated only once in 24 hours at 5am. You can customize the update schedule depending upon your requirements.

OAB Update

Where exactly are these oab files stored? On a default installtion, the oab files are stored in C:Program FilesMicrosoftExchange ServerExchangeOAB. This folder is shared so that it can be replicated to the CAS server for web distribution.

ExchangeOAB

How does oab end up in public folders? Outlook 2003 and previous versions get oab from the system public folders in exchange. The oab generation server opens the oab folders and updates the file. The oabgen.dll file is responsible for connecting to the public folder.

How does Outlook 2007 get oab files? The server that has the client access role installed (CAS server) is responsible for providing oab files for outlook 2007 clients. For that, CAS server runs a service named Microsoft Exchange File Distribution Service which copies the oab files from the mailbox server (ExchangeOAB folder) to the web distribution point in the CAS server.

File Distribution Service

Where is this web distribution point, one might ask? The web distribution folder is a folder in the file system where the copied oab files are placed. The default location is C:Program FilesMicrosoftExchange ServerClientAccessOAB.

CAS oab

The web distribution point is updated once in 8 hours. If you want to force an oab update, restart the Exchange File Distribution Service.

Now that you know how oab works and are replicated from the mailbox server to the system folders and web distribution point, you will find it much easier to troubleshoot any issues relating to the offline address book.

29 Comments

  1. Nice and useful information. …

    1. Rajith Jose Enchiparambil says:

      Thanks Prashant

  2. Hi,

    This was really very helpful explanation.

    Thanks for your efforts

    1. Rajith Jose Enchiparambil says:

      Thanks Shafiq

  3. riteshcpatil@yahoo.co.in says:

    excellent article

    1. Rajith Enchiparambil says:

      Thanks Ritesh.

  4. Muthupandi says:

    Very good to know the ground level knowledge of OAB. Thanks Rajith

    1. Rajith Enchiparambil says:

      Pleasure is mine Muthupandi

  5. BhaskarBalivada says:

    Very use full article, thank you very much

    1. Rajith Enchiparambil says:

      Thanks Bhaskar

  6. Rajith Jose Enchiparambil says:

    Thanks

  7. Anonymous says:

    If I need to download all my Offline Address Book entries onto a file, without Outlook, just a plain test program to cache all the Global Address List entries, how can I achieve that?

    ResolveNames gets me the entries with a live search, but I need them cached in my application.

  8. Anonymous says:

    Ok…can you tell me where i will set these exchange urls

  9. Rajith Jose Enchiparambil says:

    That's the reason. You need tto set all Exchange urls.

  10. Anonymous says:

    No .. it said autodiscover error….

  11. Rajith Jose Enchiparambil says:

    If you right click Outlook icon in the system tray (holding the Ctrl key down)and run "Test Email COnfiguration", is it showing the correct urls for all Exchange webs ervices?

  12. Anonymous says:

    it is exchange 2007 sp3 with Hub/CAS nlb on two nodes & SCC mailbox cluster and outlook version is 2007.

  13. Rajith Jose Enchiparambil says:

    Hi,

    Is it Exchange 2007 or 2010 & which Outlook version?

  14. Anonymous says:

    I have done all the steps but i amnot able to download OAB on outlook client. it stated an error "Microsoft Exchange object not found"

  15. Rajith Jose Enchiparambil says:

    Thanks Sanjay.

  16. wow….simple and very clear…thank you so much

  17. Rajith Jose Enchiparambil says:

    Thanks Anonymous

  18. Rajith Jose Enchiparambil says:

    Thanks Anonymous.

  19. Anonymous says:

    Good, straightforward article, just what i've been looking for! Thank you!

  20. Rajith Jose Enchiparambil says:

    Thanks Ranjeet.

  21. Excellently explained article. Full Marks!

    -Ranjeet

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