A customer of mine is running CRM 4 in IFD mode on a Windows Server 2008 R2 and I thought it might be a good idea to activate the Email router and talk to them about sending mail using that instead of the internal email handler to reduce the need for them to be online with their Outlooks for things to work.
Well, as usually I set up the email router on the CRM-server but was baffled when I couldn't connect to it. I just got this weird error of 401 Unauthorized error. I tried everthing, changing the users, adding the user to the privusergroup, changing the ADWebApplicationRootDomain. After some googling I found the solution on this excellent blog.
It turned out that the server was using IPv6 to access itself and the onpremise exceptions set up in the IFD settings were only based on IPv4 hence it tried to access it in the IFD mode. I just switched IPv6 off in the network adpater and everything worked as it should.
If you speak swedish, there are some interesting discussions on http://www.crmforum.se/, the only Swedish CRM-forum dedicated to Dynamics CRM. So head over there and digg in!
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