My list of Exchange 2010 Migration Considerations and Prerequisites

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There are many considerations and prerequisites to keep in mind for a successful implementation, and many customers do not want a “Big Bang” approach to moving to Exchange 2010.

So, I thought somewhat apprehensively – for my very first ever blog in my 16 years of working as an IT professional – I would put a little list which I have gathered through the journey.

Before you start:

Reproduce your correct Exchange 2003 / AD environment in an isolated test lab. This will require you to get hold of some hardware(Use a hyper-visor product! VMware, Hyper-V etc), and of course will require time as you reconfigure certain aspects of the infrastructure that you do not bring into the lab. The times that I have found oddities – especially customisations to environments – in the lab has saved time (and grey hairs) and also prevented unnecessary “tweaking & fiddling” in the production environment. Everyone talks about this step – people seldom really do it.
Size Server Correctly – there are more than enough tools and whitepapers to help you through this, the MSExchange Team’s blog has a super calculator which you can download. Be sure to get a good sample of past mail traffic statistics. Further to this, refer to Microsoft’s Technet Library on Exchange 2010 and review each Server role’s sizing requirements.
Understand port requirements - we always seem to scamble around for this – well scramble no more – have a look at this list for all the ports needed (it’s a short list)
Prerequisites ensure that you have these at hand BEFORE you start – and see that you deploy the hotfixes AFTER .Net :-) find a list here
Clean up DNS - DNS is vital to the health of Active Directory and Exchange, ensure that old records are cleaned out and that records which should be there are there! I have very often found records for domain controllers advertising services in a site to which they do not belong to – unintentionally causing clients to authenticate over links which they shouldnt be. Use DCDIAG /test:DNS ; and also DNSLint to check over the health. Another common ”eek” is broken delegation errors – found with DCDIAG, which often are due to erroneous creation of DNS zones (mycompany.com.mycompany.com for example) Get rid of these…but if you find there are real broken delegation issues - refer to Microsoft’s Technet Library on DNS
Check Replication Replmon days are gone, get used to repadmin; in this case to start use repadmin /replsummary as a starting point.
AD Check Site Configuration in AD Exchange 2010 no longer uses Routing Groups – it is entirely dependant on Active Directory site. Ensure that subnet to site assignments are correct!
Run the Exchange Pre-Deployment Analyzer Download Here
Obtain Unified Messaging /SAN (Subject Alternative Name) certificates for Client Access functions
Ensure that Permissions are correct in Active Directory - this is usually done automatically with the Exchange Setup process, however I feel better about manually executing the tasks to ensure that they are done, especially when you expect to co-exist for a while. [Thanks Nicolas! ]

Some problems I have encountered:

PowerShell site has missing modules
- Here one isn’t able to start the Exchange Management Console, or connect to the new server using the EMS.
- When you inspect the PowerShell site’s modules it’s found that the kerauth and WSMan modules are either incomplete or missing
- Refer to the Exchange Team’s Blog Article for details on repairing this.
New Exchange 2010 servers will not initiate (Initialization failed – No Exchange Servers are available in any AD sites)
- Find MSADAccess 2808 in event log – this is the crux of the error and ultimately the main smoking gun. The event log refers to the SACL’s for the DC’s being unable to read certain attributes – which i *think* is specifically Read to nTSecurityDescriptor
  - Refer to this blog to see what the SACL’s should look like (which incidentally also refers to the issue I am speaking of here
MSEXCHANGETOPOLOGYSERVICE Topology discovery failed, DSC_E_NO_SUITABLE_CDC
- This one really had me going – I am fairly sure I read the entire internet but found similar problems and LOTS of solutions – of which none worked for me. Here is a list of all the suggestions:
  - Install WinRM for IIS on the Windows 2008 R2 server (made zip.zero.nada difference)
  - Enable IPV6 (made no diffs if i had it manually enabled, or disabled – partially or fully)
  - Ensure that the Exchange computer accounts are members of “Exchange Servers” group in AD (I found Exchange 2010 SP1 did this during install)
- The solution that I ended up being able to repeat on all the servers was, before installing the server, adding it’s computer account to the Exchange 2003 created Exchange Domain Servers group.

Lastly:

Learn how to use PowerShell! it’s scary, it’s powerful, it’s the foundation of Exchange 2010 management….and pretty much everything else soon!
Read books! Some of my favourites are Exchange 2010 Best Practices (MS Press) ; Exchange 2010 – A practical Approach(ISBN: 978-1-906434-31-1); and Exchange 2010 Administrator’s Pocket Consultant (MSPress).