wp-admin/post.php hangs

I posted a couple of days ago about this. I have a better idea of what’s going on now, but I don’t know how to fix it. After doing some PHP debugging, I’ve found that whenever I publish a new post or save a published post that has a link in it, WP appears to be opening connections to those servers. I guess it’s not getting what it wants from those servers, because the connections hang which, in turn, hangs the web server. At that point my site is dead. I unchecked “Attempt to notify any Weblogs linked to from the article” on the Discussion options, but it is still doing this. Is this a bug?