I know this can be achieved through using plugins, but I thought WordPress handled redirection from http://www.domain.com to domain.com or vice versa, as well as domain.co.uk to domain.com. However, I've just done some testing on a couple of sites and it's not doing it.
I thought it might be something to do with All in One SEO Pack, so I disabled that to see if it made a difference, but it didn't. Looking at wp-includes/canonical.php it doesn't seem to check the hosts. All the checks are related to whether the post/page requested is correct, and that's domain independent.
What am I missing? Have I just set something up wrong?