diff --git a/docs/ikev2-howto-zh.md b/docs/ikev2-howto-zh.md
index cc7e1c3..1ebb1cb 100644
--- a/docs/ikev2-howto-zh.md
+++ b/docs/ikev2-howto-zh.md
@@ -407,13 +407,15 @@ To customize IKEv2 or client options, run this script without arguments.
    fi
    ```
 
+   **注：** 如果你在上面的第一步指定了服务器的域名（而不是 IP 地址），则必须将以下命令中的 `leftid=$PUBLIC_IP` 换成 `leftid=@$PUBLIC_IP`。
+
    ```bash
    cat > /etc/ipsec.d/ikev2.conf <<EOF
 
    conn ikev2-cp
      left=%defaultroute
      leftcert=$PUBLIC_IP
-     leftid=@$PUBLIC_IP
+     leftid=$PUBLIC_IP
      leftsendcert=always
      leftsubnet=0.0.0.0/0
      leftrsasigkey=%cert
diff --git a/docs/ikev2-howto.md b/docs/ikev2-howto.md
index 63b2c6d..23777ed 100644
--- a/docs/ikev2-howto.md
+++ b/docs/ikev2-howto.md
@@ -407,13 +407,15 @@ As an alternative to using the [helper script](#using-helper-scripts), advanced
    fi
    ```
 
+   **Note:** If you specified the server's DNS name (instead of its IP address) in step 1 above, you must replace `leftid=$PUBLIC_IP` in the command below with `leftid=@$PUBLIC_IP`.
+
    ```bash
    cat > /etc/ipsec.d/ikev2.conf <<EOF
 
    conn ikev2-cp
      left=%defaultroute
      leftcert=$PUBLIC_IP
-     leftid=@$PUBLIC_IP
+     leftid=$PUBLIC_IP
      leftsendcert=always
      leftsubnet=0.0.0.0/0
      leftrsasigkey=%cert
diff --git a/extras/ikev2setup.sh b/extras/ikev2setup.sh
index 518a7ae..b236f1b 100644
--- a/extras/ikev2setup.sh
+++ b/extras/ikev2setup.sh
@@ -917,7 +917,6 @@ cat > /etc/ipsec.d/ikev2.conf <<EOF
 conn ikev2-cp
   left=%defaultroute
   leftcert=$server_addr
-  leftid=@$server_addr
   leftsendcert=always
   leftsubnet=0.0.0.0/0
   leftrsasigkey=%cert
@@ -942,6 +941,16 @@ conn ikev2-cp
   encapsulation=yes
 EOF
 
+  if [ "$use_dns_name" = "1" ]; then
+cat >> /etc/ipsec.d/ikev2.conf <<EOF
+  leftid=@$server_addr
+EOF
+  else
+cat >> /etc/ipsec.d/ikev2.conf <<EOF
+  leftid=$server_addr
+EOF
+  fi
+
   case $swan_ver in
     3.2[35679]|3.3[12]|4.*)
       if [ -n "$dns_server_2" ]; then