There is one thing you oughtn’t do in multi-domain environment. Ever. We did it, as it was needed to successfully connect Cisco Click-to-call plug-in for Sametime with Cisco Presence server.

What is it?

Don’t change UserId in names.nsf database. OK. So I am not entirely truthful. You can do that, but make sure you add previous UserId to Username field.  But if you don’t, in best case, you can expect angry calls from your users, as e-mails from alternative domains will not be delivered to them. That’s your best case. Worst case is, no one will know and you will lose customers. Lucky for us, we had best case scenario.