diff --git a/udp_linux.go b/udp_linux.go
index a26ef05..f421275 100644
--- a/udp_linux.go
+++ b/udp_linux.go
@@ -11,7 +11,7 @@ import (
 
 func setOpts(conn syscall.RawConn) (mtud, ecn bool) {
 	_ = conn.Control(func(fd uintptr) {
-		if err := unix.SetsockoptInt(int(fd), unix.IPPROTO_IP, unix.IP_MTU_DISCOVER, unix.IP_PMTUDISC_DO); err == nil {
+		if err := unix.SetsockoptInt(int(fd), unix.IPPROTO_IP, unix.IP_MTU_DISCOVER, unix.IP_PMTUDISC_PROBE); err == nil {
 			mtud = true
 		}
 	})