OAB PDN changes and existing site consolidations

With Exchange 5.5 coming to the end of its support life cycle, lots of companies have been migrating quickly from Exchange 5.5 to Exchange 2000 or Exchange 2003. One major component that is affected by mixed mode site migrations/consolidation is the OAB. So with that being said Dave Goldman took a few minutes to share my knowledge with everyone around troubleshooting OAB PDN changes.


His write-up covers the following:


What is a PDN table?

The causes for PDN table changes

New default behavior with Exchange 2003 SP2

How to troubleshoot and Isolation of PDN table changes

Site Consolidations and PDN table changes

How to fix the PDN table changes

Effects that PDN table change can have on a network

– Overall Duration of the OAB Download

– Network Saturation

– How can all of the outlook downloads saturate a WAN?

Minimizing the side effects of Full OAB Downloads caused by PDN table changes

– Limit Large Sets of Full OAB download

– Limit Impact of a full OAB download

– Consider a Remote OAB Only Server for Remote Outlook clients


To read it – head over here – an excellent read!


Nino Bilic

Comments (2)
  1. Mikw says:

    Good article, but: why is it available so late? Probably just few people really understood before installing Exchange 2003 what’s going to happen with full OAB downloads and how much it’s going to bug their networks! MS/MCS never pointed out Exchange 5.5 <-> 2003 sync as the source of permanent full OAB downloads. And workarounds are just ridiculous – "install OAB only server". Guys, the main "selling" point for Exchange 2003 is consolidation and not istallation of additional servers in every single small office bugged by regular OAB regenerations!

    Hopefully we won’t have such "nice" surprises with next versions of Exchange.

  2. As to why it is so late, I can not answer that. I can tell you with all the work I have been doing, I work it and post it for everyone :)

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