Many of our users need to connect to the Exchange server at another organization. The other organization has Outlook Anywhere and Autodiscover setup properly and everything works properly for their internal users.
After we configure an Outlook profile for our domain users using autodiscover, there is a ~60 second delay before they are prompted for their (other organization's) username and password. We have discovered that we can check both "On Fast Networks..." and "On Slow Networks..." and the password prompt appears immediately. This is fine, and will work for our users.
However, during my testing, I discovered that when configuring Outlook on a NON-Domain computer, I do not need to check the "On Fast Networks..." box. NON-Domain computers are able to authenticate immediately.
I want to make sure that I'm not just hiding a problem here, and ensure that I understand how and WHY this is working. Does Outlook Anywhere behave differently when used on a Domain joined computer?
Per this article, it would appear that the Fast/Slow setting should only change based on adapter link speed. But it seems like something else is at play here.
This turned out to be a DNS configuration problem. For some reason that I will never understand, this client was using a local host file to resolve certain domain names. One of the entries in here included the host name of the internal mail server, but pointed to an old IP address. Essentially, Outlook attempted to look up the internal address and received an IP, so it assumed that it should be connectable. It wasn't. Removing this old entry resolved the problem.
As for the domain/non-domain issue: When the on site IT techs setup a domain computer, they push out this hosts file as part of their deployment process. When I tested with a brand new computer, I didn't use their deployment process, so I did not receive the hosts file.
Mystery solved.