Blogs not sending pings

Trackbacks work, but not pings. None of the sites on my ping list get pinged (technorati, pingomatic, etc.). I’ve read a bunch of other posts about this but none ever got resolved that I could find.

I’m running 5 blogs, all started on WP 2.0 and now run 2.0.3 and none of them send pings to the sites on the list, I have to do it manually (which sucks).

How can I resolve this problem? Whether it’s a WP problem or an issue with my server setup I dunno. I’ve got all the required software versions.