OK. I’ve been on this for 20 hours straight and I think I finally figured it out. My goal was to enable CNAME only mapping, handling both www.foosite.com and foosite.com — with no worry about a dedicated/static IP address and with the goal of the clients to ONLY have to update their nameservers at the registrar, not have them try to deal with CNAME or A records. Oh, and I’m on a CPanel host so I have no access to Apache config, or logs.
I should probably write this up somewhere but the net is:
1. Amazon AWS Route 53 handles the DNS, create a hosted zone for the client’s registered domain (foosite.com) with a www CNAME pointing to www.mymultisite.com
2. Set up an S3 bucket in Amazon AWS for the (non-www) client’s foosite.com and statically map that to www.foosite.com
3. Back in the Route 53 hosted zone, create an A record for the (non-www) foosite.com and specify it as an Alias, pointing it to the bucket created in step 2. This assures that both www.foosite.com and foosite.com will end up pointing to www.mymultisite.com (look mom, no static IP address needed! 😉 )
4. In the multisite network, go to the client’s site in network admin and edit the site URL, changing it to www.foosite.com
5. In the CPanel account that hosts mymultisite.com specify an add-on domain called foosite.com and point it to public_html (or wherever you have WP installed). This effectively creates a virtual host record in Apache config, for the incoming mapped site.
I also tried it in Godaddy and got it to work, but not the root TLD (only www), whereas I am confident that Amazon’s Alias mechanism is handling both www and non-www nicely via the bank shot to the S3 bucket.
With this setup, all I have to do is tell my client to change their nameserver designation at their registrar to the AWS nameservers I give them — and BAM, it works.