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can someone explain GAL and OAB ?

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can someone explain GAL and OAB ? - 1.Feb.2012 12:09:39 PM

laweschan

Posts: 1
Joined: 23.Mar.2009
Status: offline

Dear,

   I am very confuse about GAL and OAB how it work. Yup I have search and read many reference but I still can't make it clearly.

   For my case, I have a production exchange 2010 sp1 rollup 6 server and using outlook 2010 as client using cache mode.

   For testing, add or delete account in exchange and I can find that the change is real time update in outlook GAL. But is this really GAL or OAB record ? Why I ask this question is : if I manually add another imap/pop account from Linux email server to outlook, this "real time" update status will not work suddenly, eg. add/delete item in exchange will not update immediately in outlook GAL.

   I have no idea why this happen, no matter how I do such as clean up outlook default path data, delete oab file, or assign the default account. Only work if I manual download address book again from exchange. So, is that outlook using cache mode should used OAB by default ? and wait for around 24 hours just like microsoft said the OAB will resync again ?

thanks

Regards,
Lawes

Post #: 1

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RE: can someone explain GAL and OAB ? - 3.Feb.2012 11:31:08 AM

pjhutch

Posts: 3578
Joined: 21.Jul.2001
From: W Yorks, England
Status: offline

This is my understanding:

A) GAL (Global Address List) is updated from the Global Catalog (which is a subset of the main Active Directory Domain) and Exchange servers use the GC to lookup and resolve users and groups. In a multi-Domain Controller environment, this is updated every 5 mins or so.

B) An OAB (Offline Address Book) is a cached/offline copy of the GAL which is automatically updated every 24 hours and tends to be used when using Outlook in Exchange Cached mode. Users will not see new users straight away.

_____________________________

Peter Hutchison MCP
Exchange Administrator
University of Huddersfield

(in reply to laweschan)

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RE: can someone explain GAL and OAB ? - 11.Mar.2012 7:50:43 PM

jcman23

Posts: 36
Joined: 6.Apr.2011
Status: offline

Yes, the (GAL) global address list itself is the master list if you will of all the address objects as defined by ad. The OAB, offline address book is a copy of that that is made available for end-user clients to store on their local machine.
The global catalog is the read only copy of ad that contains the information about those objects, to query them in ad for logon purposes, and lookup for profile creation.

SO (gal) master list on server in ad,
(OAB), copy of gal for outlook clients.

_____________________________

MCTS Exchange 2010, MCSA, MCP, Security+, A+ IT Technician

(in reply to pjhutch)

Post #: 3