Avoid EPSV after failure

client_test.go

@@ -13,15 +13,7 @@ const (
 	testDir  = "mydir"
 )
 
-func TestConnPASV(t *testing.T) {
-	testConn(t, true)
-}
-
-func TestConnEPSV(t *testing.T) {
-	testConn(t, false)
-}
-
-func testConn(t *testing.T, passive bool) {
+func TestConn(t *testing.T) {
 	if testing.Short() {
 		t.Skip("skipping test in short mode.")
 	}
@@ -31,10 +23,6 @@ func testConn(t *testing.T, passive bool) {
 		t.Fatal(err)
 	}
 
-	if passive {
-		delete(c.features, "EPSV")
-	}
-
 	err = c.Login("anonymous", "anonymous")
 	if err != nil {
 		t.Fatal(err)

ftp.go

@@ -24,10 +24,11 @@ const (
 
 // ServerConn represents the connection to a remote FTP server.
 type ServerConn struct {
-	conn     *textproto.Conn
-	host     string
-	timeout  time.Duration
-	features map[string]string
+	conn       *textproto.Conn
+	host       string
+	timeout    time.Duration
+	features   map[string]string
+	epsvFailed bool
 }
 
 // Entry describes a file and is returned by List().
@@ -226,7 +227,12 @@ func (c *ServerConn) openDataConn() (net.Conn, error) {
 		err  error
 	)
 
-	if port, err = c.epsv(); err != nil {
+	if !c.epsvFailed {
+		if port, err = c.epsv(); err != nil {
+			c.epsvFailed = true
+		}
+	}
+	if c.epsvFailed {
 		if port, err = c.pasv(); err != nil {
 			return nil, err
 		}