Snow Leopard Server FTP errors
Out of the box, Snow Leopard FTP server doesn't allow loopback FTP access, it give an error:
"Address family not supported by protocol family"
The fix is:
sudo /usr/libexec/PlistBuddy -c "add :Sockets:Listeners:SockFamily string IPv4" /System/Library/LaunchDaemons/xftpd.plist
The best thing about this: there is actually a program in libexec called PlistBuddy.