Firefox will suddenly and randomly be unable to find a server for 2-3 minutes, and will end without warning. Happens infrequently, about 1 in 30 sites. Happens with links, bookmarks, and search results. Other sites can load fine, and other browsers (Safari 5) will load the currently hanging site fine--haven't used Safari enough to see if it suffers this problem with other sites. Will even cause problems with embedded images. Happens with all sites hosted by the same server (for example, all en.wikipedia.org sites will be inaccessible). Should be no firewall issues, but removed and readded Firefox to the allowed list anyway. Cleared cache and cookies. Been going on for 2-3 days.