diff --git a/client/main.go b/client/main.go
index b9667e4..1f6709c 100644
--- a/client/main.go
+++ b/client/main.go
@@ -98,7 +98,7 @@ func main() {
 		cli.StringFlag{
 			Name:  "remoteaddr, r",
 			Value: "vps:29900",
-			Usage: "kcp server address",
+			Usage: `kcp server address, eg: "IP:29900" a for single port, "IP:minport-maxport" for port range`,
 		},
 		cli.StringFlag{
 			Name:   "key",
diff --git a/server/main.go b/server/main.go
index 1cf4d3b..e25a771 100644
--- a/server/main.go
+++ b/server/main.go
@@ -133,7 +133,7 @@ func main() {
 		cli.StringFlag{
 			Name:  "listen,l",
 			Value: ":29900",
-			Usage: "kcp server listen address",
+			Usage: `kcp server listen address, eg: "IP:29900" for a single port, "IP:minport-maxport" for port range`,
 		},
 		cli.StringFlag{
 			Name:  "target, t",