diff --git a/docs/clients-zh.md b/docs/clients-zh.md
index 548fdae..4f94c4d 100644
--- a/docs/clients-zh.md
+++ b/docs/clients-zh.md
@@ -498,8 +498,8 @@ noipdefault
 defaultroute
 usepeerdns
 connect-delay 5000
-name $VPN_USER
-password $VPN_PASSWORD
+name "$VPN_USER"
+password "$VPN_PASSWORD"
 EOF
 
 chmod 600 /etc/ppp/options.l2tpd.client
diff --git a/docs/clients.md b/docs/clients.md
index 62ebebf..f6335e8 100644
--- a/docs/clients.md
+++ b/docs/clients.md
@@ -497,8 +497,8 @@ noipdefault
 defaultroute
 usepeerdns
 connect-delay 5000
-name $VPN_USER
-password $VPN_PASSWORD
+name "$VPN_USER"
+password "$VPN_PASSWORD"
 EOF
 
 chmod 600 /etc/ppp/options.l2tpd.client