Hi, We have a client and are going to bring the email from a company they bought out to their 2010 server (single server). They currently have a different domain name and I was looking through some guides that stated that we should direct their autodiscover to a new website on the 2010 server that redirects to the default site that hosts EWS. Any reason we can't just use a CNAME in the one domain to point to the default web site? For example autodiscover.maindomain.com CNAME points to mail.maindomain.com - works fine right now. autodiscover.newcompany.com CNAME points to mail.maindomain.com ???

The main reason is for SSL certificate acceptance. If you have autodiscover on the existing SSL certificate then you are simply adding an additional step to the autodiscover process. Just point the A record for autodiscover at the same IP address as the mail DNS entry. CNAME doesn't change what the client is looking for on the SSL certificate, it is just a DNS trick underneath. Therefore you have three options. 1. Get your existing SSL certificate reissued, to include autodiscover.example.com (where example.com is the new domain that is being added to Exchange). 2. Use the redirect option as already advised. 3. Use SRV records, if the DNS host for the new domain supports them. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

Ahh I completely overlooked SSL! Thanks!