diff --git a/README.md b/README.md
index 08680c1..c493952 100644
--- a/README.md
+++ b/README.md
@@ -72,8 +72,22 @@ cpxy rebind
 cpxy status | logs
 cpxy auth --user u --pass p
 cpxy auth --show | --clear
+cpxy watch status   # WWAN 自动监控
+cpxy watch once     # 手动跑一轮检查
 ```
 
+### 重拨 / `rep=0x01` 自愈
+
+| 层级 | 做法 |
+|------|------|
+| **绑定（推荐）** | 默认 `BIND_SOURCE_IP=false`：只 `bind_interface=wwanX`，**不 pin 私网源 IP**，重拨换地址通常不用 regenerate |
+| **监控** | `cellular-proxy-watch`：`ip monitor` 事件 + 60s 轮询；网卡改名/掉线/仍 pin 了 stale IP 时自动 `generate` |
+| **兜底 timer** | 每 2 分钟 oneshot 再检查一次 |
+| **手动** | `cpxy rebind && cpxy verify` |
+
+关监控：`ENABLE_CELLULAR_WATCH=false` 后 `cpxy upgrade`，或 `cpxy watch stop`。  
+若必须 pin 源 IP：`BIND_SOURCE_IP=true`（依赖 watch 同步，否则会再次 stale）。
+
 - 代理：`LAN-IP:7890`（HTTP + SOCKS5）  
 - 面板：`http://LAN-IP:9090/ui/`（密钥在安装结束输出 / `settings.conf`）  
 - **UI 可直接配置代理账号密码**（管理 API 默认 `9091`，与面板 secret 相同）
diff --git a/config/settings.conf.example b/config/settings.conf.example
index 507dc78..27141cd 100644
--- a/config/settings.conf.example
+++ b/config/settings.conf.example
@@ -17,12 +17,20 @@ LOG_DIR=/var/log/cellular-proxy
 # ---- 数据网卡（代理出口强制绑定）----
 # 留空则自动探测 wwan/usb/enx 等；建议手动填准
 CELLULAR_IFACE=
-# 可选：数据侧源 IPv4（一般留空）
+# 元数据：数据侧当前源 IPv4（generate/watch 会更新；默认不写入 sing-box）
 CELLULAR_SOURCE_IP=
+# 是否把源 IP pin 进 sing-box inet4_bind_address
+# false（默认，推荐）：只 bind_interface=网卡名 → WWAN 重拨换私网 IP 时通常无需 regenerate
+# true：额外写 inet4_bind_address（需 watch/rebind 同步，否则易 stale → SOCKS rep=0x01）
+BIND_SOURCE_IP=false
 # 数据网卡不存在则不启动（推荐 true，避免代理静默从 WiFi 出）
 REQUIRE_CELLULAR_IFACE=true
 # 自动探测关键词（逗号分隔）
 CELLULAR_IFACE_PATTERNS=wwan,wwp,usb,enx,ppp,cdc
+# 后台监控（推荐开）：网卡改名/掉线/无 IPv4 时自动 rebind；默认开启 long-running watch
+ENABLE_CELLULAR_WATCH=true
+# watch 轮询兜底间隔秒（事件驱动 ip monitor 为主）
+WATCH_INTERVAL_SEC=60
 
 # ---- 代理监听（局域网其它设备用 0.0.0.0）----
 # mixed = 同一端口同时支持 HTTP 代理 与 SOCKS5
diff --git a/scripts/generate.sh b/scripts/generate.sh
index 61dd282..d6396c7 100755
--- a/scripts/generate.sh
+++ b/scripts/generate.sh
@@ -14,22 +14,33 @@ if [[ -z "$cell" ]]; then
   resolve_cellular >/dev/null || true
 fi
 
-# 始终以当前网卡实 IP 为准：WWAN 重拨后 iface 名常不变，但 CELLULAR_SOURCE_IP 会过期。
-# 过期的 inet4_bind_address 会导致 sing-box 出站失败 → 客户端 SOCKS rep=0x01。
+# 绑定策略（优先更好的实现，而不是只靠定时器修 stale IP）：
+#   默认 BIND_SOURCE_IP=false → 只写 bind_interface，不写 inet4_bind_address。
+#   sing-box 1.11+ 在 wwan 重拨后仍能按网卡出口，无需锁定私网源 IP。
+#   实测：去掉 inet4_bind_address 后 SOCKS 仍从数据出口出（公网 IP ≠ WiFi）。
+#   BIND_SOURCE_IP=true 时才 pin 源 IP（兼容特殊内核/多地址场景），并始终用 live IP。
 live_src=""
 if [[ -n "$cell" ]]; then
   live_src="$(detect_source_ip "$cell" || true)"
 fi
 src_ip="${live_src:-${CELLULAR_SOURCE_IP:-}}"
+BIND_SOURCE_IP="$(echo "${BIND_SOURCE_IP:-false}" | tr '[:upper:]' '[:lower:]')"
 if [[ -n "$cell" && -n "$live_src" && "${CELLULAR_SOURCE_IP:-}" != "$live_src" ]]; then
-  info "源 IP 已漂移: ${CELLULAR_SOURCE_IP:-<空>} → $live_src，写回 settings"
+  info "源 IP 记录更新: ${CELLULAR_SOURCE_IP:-<空>} → $live_src（settings 仅作元数据）"
   persist_cellular_to_settings "${CONFIG_FILE:-$ROOT_DIR/etc/settings.conf}" "$cell" "$live_src" || true
-  # 兼容 live 安装布局：settings 在 etc/
   if [[ -f /opt/cellular-proxy/etc/settings.conf ]]; then
     persist_cellular_to_settings /opt/cellular-proxy/etc/settings.conf "$cell" "$live_src" || true
   fi
   CELLULAR_SOURCE_IP="$live_src"
 fi
+# 默认不把源 IP 写进 sing-box，避免下次重拨 stale bind
+GEN_SRC_FOR_CFG=""
+if [[ "$BIND_SOURCE_IP" == "true" || "$BIND_SOURCE_IP" == "1" || "$BIND_SOURCE_IP" == "yes" ]]; then
+  GEN_SRC_FOR_CFG="$src_ip"
+  info "BIND_SOURCE_IP=true → pin inet4_bind_address=${GEN_SRC_FOR_CFG:-<空>}"
+else
+  info "绑定模式: bind_interface only（不 pin 源 IP，重拨更稳）"
+fi
 
 if [[ -z "$cell" ]]; then
   warn "CELLULAR_IFACE 为空，临时用 lo 生成配置（启动前务必修正）"
@@ -47,7 +58,7 @@ fi
 
 export GEN_OUT="$OUT_DIR/config.json"
 export GEN_CELL="$cell_for_cfg"
-export GEN_SRC="$src_ip"
+export GEN_SRC="${GEN_SRC_FOR_CFG:-}"
 export GEN_PROXY_HOST="$PROXY_LISTEN_HOST"
 export GEN_PROXY_PORT="$PROXY_MIXED_PORT"
 export GEN_PROXY_USER="$PROXY_USER"
@@ -83,12 +94,13 @@ inbound = {
 if users:
     inbound["users"] = users
 
-# 唯一业务出口：强制绑定数据网卡
+# 唯一业务出口：强制绑定数据网卡（默认仅 bind_interface）
 out_cell = {
     "type": "direct",
     "tag": "cellular",
     "bind_interface": cell,
 }
+# 仅当 GEN_SRC 非空（BIND_SOURCE_IP=true）时 pin 源 IP
 if src:
     out_cell["inet4_bind_address"] = src
 
diff --git a/scripts/install.sh b/scripts/install.sh
index 7f3f2f2..6b45e2c 100755
--- a/scripts/install.sh
+++ b/scripts/install.sh
@@ -160,6 +160,23 @@ case "$cmd" in
   auth)
     exec "$BASE/scripts/apply-proxy-auth.sh" "$@"
     ;;
+  watch)
+    case "${1:-status}" in
+      once) exec "$BASE/scripts/watch-cellular.sh" --once ;;
+      status)
+        systemctl status cellular-proxy-watch.service --no-pager 2>/dev/null || true
+        systemctl status cellular-proxy-watch.timer --no-pager 2>/dev/null || true
+        ;;
+      start|enable)
+        systemctl enable --now cellular-proxy-watch.service cellular-proxy-watch.timer 2>/dev/null || true
+        ;;
+      stop|disable)
+        systemctl disable --now cellular-proxy-watch.service cellular-proxy-watch.timer 2>/dev/null || true
+        ;;
+      logs) journalctl -u cellular-proxy-watch -n "${2:-80}" --no-pager ;;
+      *) exec "$BASE/scripts/watch-cellular.sh" "$@" ;;
+    esac
+    ;;
   upgrade)
     # 一条命令在线增量升级（保留密钥/网卡）
     if [[ -x "$BASE/scripts/online-upgrade.sh" ]]; then
@@ -178,6 +195,7 @@ cpxy — cellular-proxy
   cpxy verify | logs [N]
   cpxy auth --user U --pass P   # 设置 7890 代理账号密码
   cpxy auth --clear | --show
+  cpxy watch [status|once|start|stop|logs]  # WWAN 自动监控
   cpxy upgrade                  # 一条命令在线增量升级
   cpxy upgrade --ui-only        # 只更新面板
   cpxy upgrade --force-binary   # 强制重下 sing-box
@@ -204,6 +222,19 @@ if [[ -f "$ROOT_DIR/systemd/cellular-proxy-admin.service" ]]; then
   install -m 0644 "$ROOT_DIR/systemd/cellular-proxy-admin.service" /etc/systemd/system/cellular-proxy-admin.service
   sed -i "s|@INSTALL_DIR@|$INSTALL_DIR|g" /etc/systemd/system/cellular-proxy-admin.service
 fi
+# WWAN 自动监控：事件驱动 + 定时兜底
+install_watch_units() {
+  local u
+  for u in cellular-proxy-watch.service cellular-proxy-watch-once.service cellular-proxy-watch.timer; do
+    if [[ -f "$ROOT_DIR/systemd/$u" ]]; then
+      install -m 0644 "$ROOT_DIR/systemd/$u" "/etc/systemd/system/$u"
+      sed -i "s|@INSTALL_DIR@|$INSTALL_DIR|g" "/etc/systemd/system/$u"
+      sed -i "s|@LOG_DIR@|${LOG_DIR}|g" "/etc/systemd/system/$u"
+    fi
+  done
+  chmod +x "$INSTALL_DIR/scripts/watch-cellular.sh" 2>/dev/null || true
+}
+install_watch_units
 systemctl daemon-reload
 
 info "5/6 启动服务"
@@ -239,6 +270,21 @@ else
   fi
 fi
 
+# 默认开启 watch（ENABLE_CELLULAR_WATCH!=false）
+watch_flag="$(echo "${ENABLE_CELLULAR_WATCH:-true}" | tr '[:upper:]' '[:lower:]')"
+if [[ "$watch_flag" == "false" || "$watch_flag" == "0" || "$watch_flag" == "no" ]]; then
+  systemctl disable --now cellular-proxy-watch.service cellular-proxy-watch.timer 2>/dev/null || true
+  info "ENABLE_CELLULAR_WATCH=false，未启用自动监控"
+else
+  systemctl enable cellular-proxy-watch.service 2>/dev/null || true
+  systemctl enable cellular-proxy-watch.timer 2>/dev/null || true
+  if [[ "$SKIP_START" != "true" ]]; then
+    systemctl restart cellular-proxy-watch.service 2>/dev/null || true
+    systemctl restart cellular-proxy-watch.timer 2>/dev/null || true
+  fi
+  info "已启用 cellular-proxy-watch（网卡/源 IP 变化自动 rebind）"
+fi
+
 info "6/6 自动验证出口（短超时，失败不阻塞安装结束）"
 if [[ "$SKIP_START" != "true" && "$AUTO_VERIFY" == "true" ]]; then
   set +e
diff --git a/scripts/lib.sh b/scripts/lib.sh
index aea8d62..d364866 100755
--- a/scripts/lib.sh
+++ b/scripts/lib.sh
@@ -31,8 +31,11 @@ load_config() {
   LOG_DIR="${LOG_DIR:-/var/log/cellular-proxy}"
   CELLULAR_IFACE="${CELLULAR_IFACE:-}"
   CELLULAR_SOURCE_IP="${CELLULAR_SOURCE_IP:-}"
+  BIND_SOURCE_IP="${BIND_SOURCE_IP:-false}"
   REQUIRE_CELLULAR_IFACE="${REQUIRE_CELLULAR_IFACE:-true}"
   CELLULAR_IFACE_PATTERNS="${CELLULAR_IFACE_PATTERNS:-wwan,wwp,usb,enx,ppp,cdc,rmnet,ccmni,mbim,qmi}"
+  ENABLE_CELLULAR_WATCH="${ENABLE_CELLULAR_WATCH:-true}"
+  WATCH_INTERVAL_SEC="${WATCH_INTERVAL_SEC:-60}"
   PROXY_LISTEN_HOST="${PROXY_LISTEN_HOST:-0.0.0.0}"
   PROXY_MIXED_PORT="${PROXY_MIXED_PORT:-7890}"
   PROXY_USER="${PROXY_USER:-}"
diff --git a/scripts/upgrade.sh b/scripts/upgrade.sh
index 914b7bd..3008c89 100755
--- a/scripts/upgrade.sh
+++ b/scripts/upgrade.sh
@@ -273,6 +273,23 @@ case "$cmd" in
   auth)
     exec "$BASE/scripts/apply-proxy-auth.sh" "$@"
     ;;
+  watch)
+    case "${1:-status}" in
+      once) exec "$BASE/scripts/watch-cellular.sh" --once ;;
+      status)
+        systemctl status cellular-proxy-watch.service --no-pager 2>/dev/null || true
+        systemctl status cellular-proxy-watch.timer --no-pager 2>/dev/null || true
+        ;;
+      start|enable)
+        systemctl enable --now cellular-proxy-watch.service cellular-proxy-watch.timer 2>/dev/null || true
+        ;;
+      stop|disable)
+        systemctl disable --now cellular-proxy-watch.service cellular-proxy-watch.timer 2>/dev/null || true
+        ;;
+      logs) journalctl -u cellular-proxy-watch -n "${2:-80}" --no-pager ;;
+      *) exec "$BASE/scripts/watch-cellular.sh" "$@" ;;
+    esac
+    ;;
   logs)    journalctl -u cellular-proxy -n "${1:-80}" -f ;;
   help|*)
     cat <<H
@@ -281,6 +298,7 @@ cpxy — cellular-proxy
   cpxy detect | rebind | generate | start | stop | restart | status
   cpxy verify | logs [N]
   cpxy auth --user U --pass P | --clear | --show
+  cpxy watch [status|once|start|stop|logs]  # WWAN 自动监控
   cpxy upgrade                  # 一条命令在线增量升级
   cpxy upgrade --ui-only | --force-binary | --verify
 H
@@ -305,6 +323,15 @@ if [[ -f "$ROOT_DIR/systemd/cellular-proxy-admin.service" ]]; then
   install -m 0644 "$ROOT_DIR/systemd/cellular-proxy-admin.service" /etc/systemd/system/cellular-proxy-admin.service
   sed -i "s|@INSTALL_DIR@|$INSTALL_DIR|g" /etc/systemd/system/cellular-proxy-admin.service
 fi
+# WWAN 自动监控
+for u in cellular-proxy-watch.service cellular-proxy-watch-once.service cellular-proxy-watch.timer; do
+  if [[ -f "$ROOT_DIR/systemd/$u" ]]; then
+    install -m 0644 "$ROOT_DIR/systemd/$u" "/etc/systemd/system/$u"
+    sed -i "s|@INSTALL_DIR@|$INSTALL_DIR|g" "/etc/systemd/system/$u"
+    sed -i "s|@LOG_DIR@|${LOG_DIR}|g" "/etc/systemd/system/$u"
+  fi
+done
+chmod +x "$INSTALL_DIR/scripts/watch-cellular.sh" 2>/dev/null || true
 systemctl daemon-reload
 
 export SYSTEMD_PAGER=cat
@@ -335,6 +362,20 @@ else
   fi
 fi
 
+watch_flag="$(echo "${ENABLE_CELLULAR_WATCH:-true}" | tr '[:upper:]' '[:lower:]')"
+if [[ "$watch_flag" == "false" || "$watch_flag" == "0" || "$watch_flag" == "no" ]]; then
+  systemctl disable --now cellular-proxy-watch.service cellular-proxy-watch.timer 2>/dev/null || true
+  info "ENABLE_CELLULAR_WATCH=false，未启用自动监控"
+else
+  systemctl enable cellular-proxy-watch.service 2>/dev/null || true
+  systemctl enable cellular-proxy-watch.timer 2>/dev/null || true
+  if [[ "$SKIP_START" != "true" ]]; then
+    systemctl restart cellular-proxy-watch.service 2>/dev/null || true
+    systemctl restart cellular-proxy-watch.timer 2>/dev/null || true
+  fi
+  info "已启用 cellular-proxy-watch（网卡/源 IP 变化自动 rebind）"
+fi
+
 if [[ "$DO_VERIFY" == "true" && "$SKIP_START" != "true" ]]; then
   info "出口验证…"
   set +e
diff --git a/scripts/watch-cellular.sh b/scripts/watch-cellular.sh
new file mode 100644
index 0000000..ba4cc95
--- /dev/null
+++ b/scripts/watch-cellular.sh
@@ -0,0 +1,193 @@
+#!/usr/bin/env bash
+# 监控数据网卡：IP/链路变化时自动 regenerate（避免 stale bind 或网卡改名导致 rep=0x01）
+# 策略：
+#   1) 默认配置只 bind_interface（不写死源 IP）—— 多数场景无需本脚本也能自愈
+#   2) 本脚本仍负责：iface 丢失→重探、可选 BIND_SOURCE_IP 时同步源 IP、链路 down/up 后拉起
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+# shellcheck source=lib.sh
+source "$ROOT_DIR/scripts/lib.sh"
+
+CONFIG_FILE="${CONFIG_FILE:-$ROOT_DIR/etc/settings.conf}"
+if [[ ! -f "$CONFIG_FILE" && -f /opt/cellular-proxy/etc/settings.conf ]]; then
+  CONFIG_FILE=/opt/cellular-proxy/etc/settings.conf
+  ROOT_DIR=/opt/cellular-proxy
+fi
+export CONFIG_FILE
+
+load_config
+
+INTERVAL="${WATCH_INTERVAL_SEC:-60}"
+DEBOUNCE_SEC="${WATCH_DEBOUNCE_SEC:-3}"
+LOCK_DIR="${LOG_DIR:-/var/log/cellular-proxy}"
+mkdir -p "$LOCK_DIR" 2>/dev/null || true
+STATE_FILE="${LOCK_DIR}/watch.state"
+LOG_TAG="cellular-proxy-watch"
+
+logw() { printf '[%s] %s %s\n' "$(date '+%F %T')" "$LOG_TAG" "$*" >&2; }
+
+current_cfg_iface() {
+  python3 - <<'PY' 2>/dev/null || true
+import json
+from pathlib import Path
+for p in ("/opt/cellular-proxy/etc/config.json",):
+    try:
+        c=json.loads(Path(p).read_text())
+        for o in c.get("outbounds") or []:
+            if o.get("tag")=="cellular":
+                print(o.get("bind_interface") or "")
+                raise SystemExit
+    except Exception:
+        pass
+print("")
+PY
+}
+
+current_cfg_src() {
+  python3 - <<'PY' 2>/dev/null || true
+import json
+from pathlib import Path
+try:
+    c=json.loads(Path("/opt/cellular-proxy/etc/config.json").read_text())
+    for o in c.get("outbounds") or []:
+        if o.get("tag")=="cellular":
+            print(o.get("inet4_bind_address") or "")
+            raise SystemExit
+except Exception:
+    pass
+print("")
+PY
+}
+
+need_refresh() {
+  load_config
+  local cell="${CELLULAR_IFACE:-}"
+  local live_src="" cfg_iface cfg_src
+  cfg_iface="$(current_cfg_iface)"
+  cfg_src="$(current_cfg_src)"
+
+  if [[ -z "$cell" ]] || ! iface_exists "$cell"; then
+    logw "iface missing or empty (CELLULAR_IFACE=${cell:-<空>}) → rebind"
+    return 0
+  fi
+
+  live_src="$(detect_source_ip "$cell" || true)"
+  if [[ -z "$live_src" ]]; then
+    # 网卡在但无 IPv4：可能刚重拨；不立刻 die，等下一轮
+    logw "wwan up but no IPv4 yet on $cell"
+    # 若配置里仍绑旧源 IP，清掉/重生更安全
+    if [[ -n "$cfg_src" ]]; then
+      return 0
+    fi
+    return 1
+  fi
+
+  if [[ -n "$cfg_iface" && "$cfg_iface" != "$cell" ]]; then
+    logw "cfg iface $cfg_iface != settings $cell"
+    return 0
+  fi
+
+  # 仅当配置写了 inet4_bind_address 且与 live 不一致时才需要
+  if [[ -n "$cfg_src" && "$cfg_src" != "$live_src" ]]; then
+    logw "stale source IP cfg=$cfg_src live=$live_src"
+    return 0
+  fi
+
+  # settings 里的 SOURCE_IP 过期也同步（即使 config 未 pin）
+  if [[ -n "${CELLULAR_SOURCE_IP:-}" && "${CELLULAR_SOURCE_IP}" != "$live_src" ]]; then
+    persist_cellular_to_settings "$CONFIG_FILE" "$cell" "$live_src" || true
+  fi
+
+  return 1
+}
+
+do_refresh() {
+  load_config
+  local cell="${CELLULAR_IFACE:-}"
+  local src=""
+
+  if [[ -z "$cell" ]] || ! iface_exists "$cell"; then
+    cell="$(detect_cellular_iface "" || true)"
+    if [[ -z "$cell" ]]; then
+      logw "detect failed; skip"
+      return 1
+    fi
+  fi
+  src="$(detect_source_ip "$cell" || true)"
+  if [[ -z "$src" ]]; then
+    logw "no IPv4 on $cell yet; skip generate"
+    return 1
+  fi
+  persist_cellular_to_settings "$CONFIG_FILE" "$cell" "$src" || true
+  logw "refresh: iface=$cell src=$src"
+  # 走 cpxy generate（含 check + restart）；失败则直接 scripts
+  if command -v cpxy >/dev/null 2>&1; then
+    cpxy generate >/dev/null 2>&1 || {
+      # shellcheck source=/dev/null
+      source "$ROOT_DIR/scripts/lib.sh"
+      load_config
+      "$ROOT_DIR/scripts/generate.sh" "$ROOT_DIR/generated"
+      install -m 0644 "$ROOT_DIR/generated/config.json" "$ROOT_DIR/etc/config.json"
+      install -m 0644 "$ROOT_DIR/generated/runtime.env" "$ROOT_DIR/etc/runtime.env" 2>/dev/null || true
+      systemctl restart cellular-proxy 2>/dev/null || true
+    }
+  else
+    "$ROOT_DIR/scripts/generate.sh" "$ROOT_DIR/generated"
+    install -m 0644 "$ROOT_DIR/generated/config.json" "$ROOT_DIR/etc/config.json"
+    systemctl restart cellular-proxy 2>/dev/null || true
+  fi
+  printf '%s iface=%s src=%s\n' "$(date -Iseconds)" "$cell" "$src" >"$STATE_FILE" 2>/dev/null || true
+  logw "refresh done"
+}
+
+# oneshot mode (systemd timer)
+if [[ "${1:-}" == "--once" ]]; then
+  if need_refresh; then
+    do_refresh || true
+  fi
+  exit 0
+fi
+
+# long-running: periodic + optional ip monitor events
+logw "start interval=${INTERVAL}s (debounce=${DEBOUNCE_SEC}s)"
+last_run=0
+trigger() {
+  local now
+  now="$(date +%s)"
+  if (( now - last_run < DEBOUNCE_SEC )); then
+    return 0
+  fi
+  last_run=$now
+  if need_refresh; then
+    do_refresh || true
+  fi
+}
+
+# initial
+trigger
+
+# Prefer event-driven if available; always keep poll as safety net
+if command -v ip >/dev/null 2>&1; then
+  (
+    # address/link changes on any iface — cheap filter in shell
+    ip -o monitor address link 2>/dev/null | while read -r line; do
+      cell="${CELLULAR_IFACE:-}"
+      # reload cell from settings occasionally
+      if [[ -f "$CONFIG_FILE" ]]; then
+        cell="$(awk -F= '/^CELLULAR_IFACE=/{print $2; exit}' "$CONFIG_FILE" 2>/dev/null || true)"
+      fi
+      if [[ -n "$cell" ]] && [[ "$line" == *"$cell"* || "$line" == *Deleted* || "$line" == *wwan* || "$line" == *usb* || "$line" == *enx* ]]; then
+        sleep "$DEBOUNCE_SEC"
+        trigger
+      fi
+    done
+  ) &
+  mon_pid=$!
+  trap 'kill $mon_pid 2>/dev/null || true; exit 0' TERM INT
+fi
+
+while true; do
+  sleep "$INTERVAL"
+  trigger
+done
diff --git a/systemd/cellular-proxy-watch-once.service b/systemd/cellular-proxy-watch-once.service
new file mode 100644
index 0000000..8ed9191
--- /dev/null
+++ b/systemd/cellular-proxy-watch-once.service
@@ -0,0 +1,18 @@
+[Unit]
+Description=cellular-proxy WWAN watch once (timer)
+After=network-online.target
+ConditionPathExists=@INSTALL_DIR@/etc/settings.conf
+
+[Service]
+Type=oneshot
+EnvironmentFile=-@INSTALL_DIR@/etc/runtime.env
+EnvironmentFile=-@INSTALL_DIR@/etc/settings.conf
+ExecStart=@INSTALL_DIR@/scripts/watch-cellular.sh --once
+Nice=10
+MemoryMax=16M
+NoNewPrivileges=true
+ProtectSystem=full
+ProtectHome=true
+PrivateTmp=true
+StandardOutput=append:@LOG_DIR@/watch.log
+StandardError=append:@LOG_DIR@/watch.log
diff --git a/systemd/cellular-proxy-watch.service b/systemd/cellular-proxy-watch.service
new file mode 100644
index 0000000..d192d96
--- /dev/null
+++ b/systemd/cellular-proxy-watch.service
@@ -0,0 +1,25 @@
+[Unit]
+Description=cellular-proxy WWAN watch (auto rebind on IP/link change)
+After=network-online.target cellular-proxy.service
+Wants=network-online.target
+PartOf=cellular-proxy.service
+
+[Service]
+Type=simple
+EnvironmentFile=-@INSTALL_DIR@/etc/runtime.env
+EnvironmentFile=-@INSTALL_DIR@/etc/settings.conf
+# 低内存：watch 脚本本身极轻；间隔可在 settings WATCH_INTERVAL_SEC 覆盖
+ExecStart=@INSTALL_DIR@/scripts/watch-cellular.sh
+Restart=always
+RestartSec=5
+MemoryMax=16M
+Nice=10
+NoNewPrivileges=true
+ProtectSystem=full
+ProtectHome=true
+PrivateTmp=true
+StandardOutput=append:@LOG_DIR@/watch.log
+StandardError=append:@LOG_DIR@/watch.log
+
+[Install]
+WantedBy=multi-user.target
diff --git a/systemd/cellular-proxy-watch.timer b/systemd/cellular-proxy-watch.timer
new file mode 100644
index 0000000..41b57cd
--- /dev/null
+++ b/systemd/cellular-proxy-watch.timer
@@ -0,0 +1,14 @@
+[Unit]
+Description=cellular-proxy WWAN watch timer (fallback oneshot)
+Requires=cellular-proxy-watch-once.service
+
+[Timer]
+# 兜底：即使 long-running watch 挂了，也每 2 分钟 oneshot 检查
+OnBootSec=1min
+OnUnitActiveSec=2min
+AccuracySec=30s
+Persistent=true
+Unit=cellular-proxy-watch-once.service
+
+[Install]
+WantedBy=timers.target