I'm using PureFTPd on MacOSX (Snow Leopard, not server version). When trying to access the FTP account from the outside via dyndns (e.g. using https://www.wormly.com/test_ftp_server) the connection always times out the FIRST time. When I try AGAIN in the next few seconds it works. What is this about?I have forwarded the ports to my apple router and tried disabling the OSX firewall as well. 
FTP timeout FIRST time
osx;ftp