Ok, so I had set up Domain Mapping on a blog of mine previously, with lots of problems and tears. So just to increase my misery I decided to move hosts :)
Since this site wasn't officially launched and I was having issues migrating (infinite loops) I tried a fresh MU install (WP 3.5.1). I was impressed that this came together with slightly fewer issues. I managed to get it installed and running relatively easily. HOWEVER, in my previous installation I was using a subdomain installation and this one is a sub directory installation.
NOW, I have the mappings working correctly, so if I map def.com to abc.com/def/ I get the correct redirect. HOWEVER, in my previous installation I had it set up so that def.com had a symlink pointing at abc.com which then did a rewrite to write the URL back to def.com. This is what I'm looking to do, but can't seem to get it to work using sub directories.
Do I have to set this up as a subdomain installation instead, in order to get it to work the way I want? I'm wondering if maybe the issue with infinite loops could be related to my .htaccess and a lack of a proper symlink?
I have CPanel now, and I simply have the other domains Parked in my Cpanel and pointed at abc.com.
Any ideas? Any helpful setup tutorials to get it so that it will properly rewrite to the parked domain?