Leopard's firewall apparently modifies applications when you tell it to "allow" network connections. For example, in StarCraft, when you first try to log on to Battle.net after an update (for me, I just updated to 1.15.2, the no-cd version), StarCraft will complain that port 6112 is not open (which it should not be), but you can still log on to Battle.net and chat but not play games. Mac OS X will then ask you if you want to deny or allow network connections. If you click allow, it will append data to "Starcraft (Carbon)" starting at offset 155fe9, causing Starcraft to fail all further login checks for Battle.net. Battle.net checks your application to prevent cheating; the first time you are still able to log in because you're already in Battle.net by the time the data is appended. After that, Starcraft is 1.7 MB rather than 1.6 MB (actually only 8 KB have been added I think), so your application version can no longer be properly identified. Basically, Leopard's firewall is corrupting at least Starcraft, which is one of the worst possible apps to corrupt, due to Blizzard's anti-cheating mechanisms. I think the appended data just allows Mac OS X to recognize it as an allowed app. Honestly, Apple, this had better be fixed in 10.5.2 or I'm going to be pissed at this supposedly "improved" firewall. Because it's not improved; it seriously sucks some major ass.