pnlrogue1 (22nd July 2009)
I have a question about Exchange 2003 and Forest Upgrades:
I'm running Exchange 2003 on a Windows Server 2003 system with a Server 2000 Functional Level Forest and Domain, though we have no Server 2000 servers
We are looking at upgrading our DCs and Domain to 2008 but don't want to upgrade our Exchange Server - can we safely run Exchange 2003 on a Server 2003 in a 2008 domain?
Please help! I'm at my wits' end trying to trawl through the mixed, scattered advice online!
Thanks

He he I am about to click the "Raise to 2008 functionality mode" button too soon.
We are running 2000 AD right now with, like youselves, a 2003 exchange.
I am almost 100% sure it should work fine as everything I have read about functionality level says it only affects the way DC's replicate data and does not disable exchange fields/things in AD, but I have not had it confirmed.
pnlrogue1 (22nd July 2009)
If your Exchange 2003 server is only a member server it should be fine. Having said that, never tried it. But can't think of anything in theory!
The few bits I've found which cover this do seem to suggest that it should be ok, but I don't see how a Windows 2003 server can run a 2008 Active Directory
It does say on Exchange forums that Ex2003 will support Server 2008 DCs but won't install on Server 2008 itself so I'm leaning towards "It'll work"
Have cross-posted on Petri.co.il so I'll add any replies I get from there on this forum

Ohh your not meaning to increase functionality and just add a 2008 DC to a existing 2003 based AD?
If so then its completely fine as we have 2008 DC's here without issue on our 2000 level AD. We have been slowing moving out all our 2000 DC's and are at the point of raising the AD level to 2008.
EDIT: When you add a 2008 DC to a 2003 AD network it runs fine as 2008 supports all AD from 2000 Mixed mode (sp4 required on 2000 DC's) for replication so it will just continue as normal (like it did here anyway).
Last edited by ZeroHour; 22nd July 2009 at 01:13 PM.


This implies it should be fine as long as your using exchange 2003 sp2:
You Had Me At EHLO... : Exchange Server and Windows Server 2008
pnlrogue1 (22nd July 2009)
ZeroHour (22nd July 2009)

Yeh I think it will work, thats the blog of the exchange team so it should be accurate.
The difference is one is running your current functionality (which should change nothing AD wise) of AD which means that if you have old servers (NT4 or old versions of linux/unix samba) you may not be able to authenticate with the 2008 DC but you change a setting in your GP for default domain policy and it fixes that (if needed) as per a users blog here:
http://www.edugeek.net/forums/blogs/...n-gotchas.html
Running full 2008 AD has the same problem but the same fix works for it similarily. Other then that I dont *think* their are much differences that would affect exchange since 2003->2008 AD is more about password policies and replication enhancements between DC's.
See Understanding Windows Server 2008 Active Directory Domain and Forest Functional Levels as it roughly outlines the changes but who knows how exhaustive it is. I will be clicking the button today/tomorrow so if it all melts down I will let you know![]()
pnlrogue1 (22nd July 2009)

The button has been clicked, nothing has blown up yet
No errors so far with both forest and AD switched to 2008 mode.
pnlrogue1 (22nd July 2009)
Was it a big red button?
Thank you for your advice - looking forward to trying it soon![]()

He he, no it wasnt sadly, just a little exclamation mark.
Np, and good luck![]()
Just thought I'd post an update
We did update our Exchange server through MS Update and then raise the domain and forest to 2008 and have seen no problems several months on
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