Offline Address Book plays important role in Exchange Services
Offline address book(OAB) is the Local Copy downloaded to the Outlook Client Machine from the Exchange Servers for the Local Queries of address resolutions when disconnected from Exchange Servers.
Consider the following areas when you planning and implementing the Offline Address Book (OAB) in better way.
For more details on Offline Address Book (OAB) , Please refer the below Multi Part of articles
Simplified Address Lists:
Always keep Simplified Address lists in the organization Level distribution for all the users. more complex address lists brings more Complex in setting the OAB for the mailboxes.
Address lists are consists, 1. Mail Recipients and their informations. 2. Groups in the organizations. 3. Certificates available in the Certificate Services (PKI)
Simplified PKI Infrastructure 1. The more public key infrastructure (PKI) certificates, the larger the OAB. PKI certificates range from 1 kilobyte (KB) to 3 KB. They’re the single largest contributor to the OAB size. 2. Reduce Creating the more User Certificates in PKI Infrastructure.
Email addresses and recipients configuration 1. Correct all the SMTP Mismatches Addresses. in Org level, More SMTP Errors will bring the OAB issues. 2. Recipients that you’ve hidden in Active Directory by using methods outside of Exchange will be visible in OABs (for example, by using the Windows security descriptor). To effectively hide recipients in OABs, configure the Hide from address lists property for the recipient in the Exchange admin center (EAC) or the HiddenFromAddressListsEnabled parameter in the corresponding recipient management cmdlet in the Exchange Management Shell. 3. you can create an address list that doesn’t include the hidden recipients, assign the address list to the OAB, and assign the OAB to users (directly or by making the OAB the default).
Shadow Copy and GlobalWebDistributionEnabled:
If Exchange Datacenters and Users are implemented across multiple Locations, COnsider implementing Shadow Copy and GlobalWebDistributionEnabled which will reduce the network and servers Load in single load. For more details refer the article
Conditions that cause a full OAB download which may be need to be considered The improvements to OABs typically require clients to download OAB updates, not the full and complete OAB. However, full OAB downloads are sometimes required. The Changes.oab files are greater than or equal to half the size of the full OAB files. Outlook compares the total size of the compressed Changes.oab files that are required to update the OAB to the total size of the compressed full OAB files on the server.
There’s no OAB on your computer (for example, during the initial setup of Outlook).
A differential file is missing on the server. Missing differential files can be caused by the following conditions: You haven’t used Outlook to connect to your Exchange mailbox in more than 30 days (by default, the differential files are stored on the server for 30 days).
The server couldn’t generate the differential file for a day that’s required to update your local copy of the OAB.
A more recent version of the OAB is available on the server (for example, your mailbox was upgraded from Exchange 2010, and your local copy of the OAB is version 3).
Applying changes to the OAB failed. For example, differential files are corrupted on the server (the server crashed during differential file generation).
The OAB is not present on your computer (for example, you manually deleted one or more local OAB files).
A previous full download failed, so Outlook has to start over.
You initiated a manual download of the full OAB.
For more details on Offline Address Book (OAB) , Please refer the below Multi Part of articles