diff --git a/easytier/locales/app.yml b/easytier/locales/app.yml
index 120ffc8..fd84007 100644
--- a/easytier/locales/app.yml
+++ b/easytier/locales/app.yml
@@ -10,6 +10,11 @@ core_clap:
       配置服务器地址。允许格式：
       完整URL：--config-server udp://127.0.0.1:22020/admin
       仅用户名：--config-server admin，将使用官方的服务器
+  machine_id:
+    en: |+
+      the machine id to identify this machine, used for config recovery after disconnection, must be unique and fixed. default is from system.
+    zh-CN: |+
+      Web 配置服务器通过 machine id 来识别机器，用于断线重连后的配置恢复，需要保证唯一且固定不变。默认从系统获得。
   config_file:
     en: "path to the config file, NOTE: the options set by cmdline args will override options in config file"
     zh-CN: "配置文件路径，注意：命令行中的配置的选项会覆盖配置文件中的选项"
diff --git a/easytier/src/common/constants.rs b/easytier/src/common/constants.rs
index fe561f2..8361442 100644
--- a/easytier/src/common/constants.rs
+++ b/easytier/src/common/constants.rs
@@ -1,21 +1,21 @@
 macro_rules! define_global_var {
     ($name:ident, $type:ty, $init:expr) => {
-        pub static $name: once_cell::sync::Lazy<tokio::sync::Mutex<$type>> =
-            once_cell::sync::Lazy::new(|| tokio::sync::Mutex::new($init));
+        pub static $name: once_cell::sync::Lazy<std::sync::Mutex<$type>> =
+            once_cell::sync::Lazy::new(|| std::sync::Mutex::new($init));
     };
 }
 
 #[macro_export]
 macro_rules! use_global_var {
     ($name:ident) => {
-        crate::common::constants::$name.lock().await.to_owned()
+        crate::common::constants::$name.lock().unwrap().to_owned()
     };
 }
 
 #[macro_export]
 macro_rules! set_global_var {
     ($name:ident, $val:expr) => {
-        *crate::common::constants::$name.lock().await = $val
+        *crate::common::constants::$name.lock().unwrap() = $val
     };
 }
 
@@ -23,6 +23,8 @@ define_global_var!(MANUAL_CONNECTOR_RECONNECT_INTERVAL_MS, u64, 1000);
 
 define_global_var!(OSPF_UPDATE_MY_GLOBAL_FOREIGN_NETWORK_INTERVAL_SEC, u64, 10);
 
+define_global_var!(MACHINE_UID, Option<String>, None);
+
 pub const UDP_HOLE_PUNCH_CONNECTOR_SERVICE_ID: u32 = 2;
 
 pub const WIN_SERVICE_WORK_DIR_REG_KEY: &str = "SOFTWARE\\EasyTier\\Service\\WorkDir";
diff --git a/easytier/src/common/mod.rs b/easytier/src/common/mod.rs
index e8b46e7..63f9d16 100644
--- a/easytier/src/common/mod.rs
+++ b/easytier/src/common/mod.rs
@@ -8,6 +8,8 @@ use time::util::refresh_tz;
 use tokio::{task::JoinSet, time::timeout};
 use tracing::Instrument;
 
+use crate::{set_global_var, use_global_var};
+
 pub mod compressor;
 pub mod config;
 pub mod constants;
@@ -87,7 +89,17 @@ pub fn join_joinset_background<T: Debug + Send + Sync + 'static>(
     );
 }
 
+pub fn set_default_machine_id(mid: Option<String>) {
+    set_global_var!(MACHINE_UID, mid);
+}
+
 pub fn get_machine_id() -> uuid::Uuid {
+    if let Some(default_mid) = use_global_var!(MACHINE_UID) {
+        let mut b = [0u8; 16];
+        crate::tunnel::generate_digest_from_str("", &default_mid, &mut b);
+        return uuid::Uuid::from_bytes(b);
+    }
+
     // a path same as the binary
     let machine_id_file = std::env::current_exe()
         .map(|x| x.with_file_name("et_machine_id"))
diff --git a/easytier/src/easytier-core.rs b/easytier/src/easytier-core.rs
index 39d53f6..b15b0c8 100644
--- a/easytier/src/easytier-core.rs
+++ b/easytier/src/easytier-core.rs
@@ -22,6 +22,7 @@ use easytier::{
         },
         constants::EASYTIER_VERSION,
         global_ctx::GlobalCtx,
+        set_default_machine_id,
         stun::MockStunInfoCollector,
     },
     connector::create_connector_by_url,
@@ -99,6 +100,13 @@ struct Cli {
     )]
     config_server: Option<String>,
 
+    #[arg(
+        long,
+        env = "ET_MACHINE_ID",
+        help = t!("core_clap.machine_id").to_string()
+    )]
+    machine_id: Option<String>,
+
     #[arg(
         short,
         long,
@@ -936,6 +944,7 @@ async fn run_main(cli: Cli) -> anyhow::Result<()> {
     init_logger(&cli.logging_options, false)?;
 
     if cli.config_server.is_some() {
+        set_default_machine_id(cli.machine_id);
         let config_server_url_s = cli.config_server.clone().unwrap();
         let config_server_url = match url::Url::parse(&config_server_url_s) {
             Ok(u) => u,