First, let me start by saying what I did appears to be working. What I did was trivially easy, but I'm just wondering if what I did is best for SEO, maintaining page rankings, etc.
Up until a few minutes ago one of my personal domains douglerner.com went to my Posterous blog at douglerner.posterous.com.
I recently migrated my Posterous blog back to a self-hosted blog at my main personal domain, lerner.net, at Hostgator. Now my email and blog are in the same domain, it's shorter and, well, my friends say they like it that way too.
So I just changed the nameservers for douglerner.com to Hostgator's servers and created an add-on domain for it there, setting the domain root directory to be the same as that for lerner.net.
I thought I would also have to do some rewrite in .htaccess with a permanent redirect 301, but it seems to work just by doing what I did.
The paths have the same structure, and if I go to douglerner.com/some-post-title it correctly goes to lerner.net/some-post-title. And my Google searches that popup with the douglerner.com domain all have links which go to the correct post at lerner.net.
Need I worry any more about it? Or do I need to give further indications via a rewrite rule to let Google know this is a permanent redirect?