derp/derphttp/derphttp_client.go

@@ -873,7 +873,15 @@ func (c *Client) dialNodeUsingProxy(ctx context.Context, n *tailcfg.DERPNode, pr
 		}
 	}()
 
-	target := net.JoinHostPort(n.HostName, "443")
+	// Keep port selection in sync with dialNode.
+	port := "443"
+	if !c.useHTTPS() {
+		port = "3340"
+	}
+	if n.DERPPort != 0 {
+		port = fmt.Sprint(n.DERPPort)
+	}
+	target := net.JoinHostPort(n.HostName, port)
 
 	var authHeader string
 	if buildfeatures.HasUseProxy {