1. The PASV response sends the server IPv4 back to the client. If you didn't configure this to be the current external IPv4 of the server network, or it is twisted by a firewall/router (usually happens on unencrypted FTP connections using the default port 21) PASV fails. EPSV does not return an IP, only a port.
2. Especially if you have older routers/firewalls, they may simple not know EPSV and leave it alone, but fuck up PASV badly.
2. Especially if you have older routers/firewalls, they may simple not know EPSV and leave it alone, but fuck up PASV badly.
Quote:
How can I force an FTP client (FileZilla) to use ESPV?
You simply can't, at least for IPv4. Please note that IPv6 connections always use EPRT or EPSV.