Opening ports for Exchange 2010 in firewall

The Technet Documentation is really complete. Follow it to a tee. It goes over practically everything regarding getting your 2010 setup going. There's only 4 caveats that I feel are worth mentioning.

First, read up on routing group connectors. The install takes care of creating the first connector, but if you have multiple 2010 servers, you'll need to create additional connectors. Also, don't forget to create receive connectors for your old 2003 setup. You want mail to flow properly while you're in a migration. Surprisingly, I don't remember the docs talking much (or at all) about this.

Second, your legacy OWA might break. This is a situation I ran into during my first migration. You can see a discussion about it on Technet here. Basically, when a 2003 user logs onto a 2010 OWA server, they should be forwarded to a 2003 front end server. This didn't happan all so well. Setting the legacyredirecttype to manual fixed the problem, although making it a little more difficult for the end users to figure out what's happening.

Third, removing your 2003 setup isn't really touched on at all in the 2010 Technet docs. You should follow the information for 2007 available here. When instructed to uninstall Exchange 2003, simply uninstall 1 cluster node at a time. When you get to the last node, let the installer know it's the last node and it will remove the server from Active Directory.

Fourth, I don't remember the docs talking much about ActiveSync. Luckily, the Exchange team has a great blog. They definitely talked about it here.

My first migration went really well. Moved mailboxes over the weekend, came in on Monday and nobody with Outlook noticed anything other than better performance. OWA users were a little surprised, but they learned it quickly.

Try exiting outlook and going to Start - Run - outlook /safe and see if the problem reproduces.

If it does not, it might be an Outlook plug-in that's causing the issue.