Add a bool property for forcing Passive mode.

ftp.go

@@ -27,6 +27,7 @@ type ServerConn struct {
 	conn     *textproto.Conn
 	host     string
 	features map[string]string
+	Passive  bool
 }
 
 // Entry describes a file and is returned by List().
@@ -58,6 +59,7 @@ func Connect(addr string) (*ServerConn, error) {
 		conn:     conn,
 		host:     a[0],
 		features: make(map[string]string),
+		Passive:  false,
 	}
 
 	_, _, err = c.conn.ReadResponse(StatusReady)
@@ -203,7 +205,7 @@ func (c *ServerConn) openDataConn() (net.Conn, error) {
 	//  else -> PASV
 	_, nat6Supported := c.features["nat6"]
 	_, epsvSupported := c.features["EPSV"]
-	if nat6Supported || epsvSupported {
+	if !c.Passive && (nat6Supported || epsvSupported) {
 		port, err = c.epsv()
 		if err != nil {
 			return nil, err