en: update document.

en/docs/config/server-config.md

@@ -0,0 +1,74 @@
+---
+hide:
+  - toc
+---
+
+# Server Configuration
+
+Currently, smartdns provides three server modes: UDP, TCP, and DOT.
+
+## UDP Server
+
+1. Configure with the `bind` parameter. For example:
+
+    ```shell
+    bind 0.0.0.0:53@eth0
+    bind [::]:53@eth0
+    bind :53@eth0
+    ```
+
+    Options:
+
+    * @eth0 indicates that it only provides services on the corresponding NIC.
+    * [::]:53 indicates that it listens to both IPV6 and IPV4 addresses.
+    * :53 represents listening to IPV4 addresses.
+
+## TCP Server
+
+1. Configure with the `bind-tcp` parameter. For example:
+
+    ```shell
+    bind-tcp 0.0.0.0:53@eth0
+    bind-tcp [::]:53@eth0
+    bind-tcp :53@eth0
+    ```
+
+1. Optional, the `tcp-idle-time` parameter controls the TCP idle disconnect time.
+
+    ```shell
+    tcp-idle-time 120
+    ```
+
+## DOT Server
+
+1. Configure with the `bind-tcp` parameter. For example:
+
+    ```shell
+    bind-tcp 0.0.0.0:53@eth0
+    bind-tcp [::]:53@eth0
+    bind-tcp :53@eth0
+    ```
+
+1. Set certificate and key files
+
+    ```shell
+    bind-cert-file smartdns-cert.pem
+    bind-cert-key-file smartdns-key.pem
+    bind-cert-key-pass pass
+    ```
+
+    Options:
+
+    * `bind-cert-file`: Specifies the certificate file path.
+    * `bind-cert-key-file`: Specifies the certificate key file path.
+    * `bind-cert-key-pass`: Specifies the password for the certificate key file. (Optional)
+
+    Note:
+
+    If these three parameters are not specified, smartdns will automatically generate a self-signed cert `smartdns-cert.pem` and `smartdns-key.pem` key file in the `/etc/smartdns` directory, with CN as smartdns.
+
+1. Optional, the `tcp-idle-time` parameter controls the TCP idle disconnect time.
+
+    ```shell
+    tcp-idle-time 120
+    ```