TryNATFastTrack is a Boolean property that indicates if the FTP client should use "fast path" connections for traversing firewalls and network address translators (NAT). TryNATFastTrack can enhance the performance of data transfers when the FTP EPSV command is supported on the server implementation. 

TryNATFastTrack will cause the FTP EPSV ALL command to be sent after establishing the control channel for the client connection and performing authentication when the AutoLogin property contains True. EPSV ALL informs Network Address Translators that the EPRT command (as well as other data commands) will no longer be used for the client session. 

After receiving an EPSV ALL command, the server must reject all data connection setup commands other than EPSV (i.e., EPRT, PORT, PASV, et al.). This process results in the UsingNATFastTrack property being set to True on successful completion of the feature negotiation. 

The default value for TryNATFastTrack is Id_TIdFTP_UseNATFastTrack, as assigned during initialization of the component.

Connect 

AutoLogin 

UsingNATFastTrack