diff --git a/packaging/linux/install.sh b/packaging/linux/install.sh
index c3f9db1..7e61e2a 100755
--- a/packaging/linux/install.sh
+++ b/packaging/linux/install.sh
@@ -156,9 +156,12 @@ pick_port() { # pick_port <label> <value> <default> <host> <allow_current>
       [[ "${INTERACTIVE}" == "1" ]] || die "${p}"
       err "${p}"; val=""; continue
     fi
-    if [[ "${p}" == "${allow}" ]] || netx_admin port-free "${p}" --host "${host}"; then
+    local rc=0
+    [[ "${p}" == "${allow}" ]] || netx_admin port-free "${p}" --host "${host}" || rc=$?
+    if [[ "${rc}" == "0" ]]; then
       echo "${p}"; return 0
     fi
+    [[ "${rc}" == "3" ]] && die "$(t "监听地址无效" "invalid listen address"): ${host}"
     local msg
     msg="$(t "端口 ${p} 已被占用" "port ${p} is in use")"
     [[ "${INTERACTIVE}" == "1" ]] || die "port_in_use: ${p} — ${msg}"
@@ -176,13 +179,23 @@ configure() {
 
   echo
   info "$(t "配置 NetX" "Configure NetX")"
-  if [[ -z "${BIND}" ]]; then
-    if [[ "${INTERACTIVE}" == "1" ]]; then
-      BIND="$(ask "$(t "监听地址（0.0.0.0=所有网卡，127.0.0.1=仅本机）" "Listen address (0.0.0.0 = all, 127.0.0.1 = local only)")" "${old_bind:-0.0.0.0}")"
-    else
-      BIND="${old_bind:-0.0.0.0}"
+  local b
+  while :; do
+    if [[ -z "${BIND}" ]]; then
+      if [[ "${INTERACTIVE}" == "1" ]]; then
+        BIND="$(ask "$(t "监听地址（回车或 0.0.0.0 = 所有网卡；127.0.0.1 = 仅本机；或本机某个 IP）" "Listen address (Enter/0.0.0.0 = all interfaces, 127.0.0.1 = local only, or one of this server's IPs)")" "${old_bind:-0.0.0.0}")"
+      else
+        BIND="${old_bind:-0.0.0.0}"
+      fi
     fi
-  fi
+    if b="$(netx_admin norm-bind -- "${BIND}" 2>&1)"; then
+      BIND="${b}"
+      break
+    fi
+    [[ "${INTERACTIVE}" == "1" ]] || die "${b}"
+    err "${b}"
+    BIND=""
+  done
   API_PORT="$(pick_port "$(t "Web/API 端口" "Web/API port")" "${API_PORT}" "${old_port:-8890}" "${BIND}" "${old_port}")"
 
   if [[ -z "${DB_MODE}" ]]; then
diff --git a/packaging/linux/netx_admin.py b/packaging/linux/netx_admin.py
index 5379b5f..a7d4473 100644
--- a/packaging/linux/netx_admin.py
+++ b/packaging/linux/netx_admin.py
@@ -102,15 +102,50 @@ def write_env(path: Path, values: dict[str, str], unset: list[str] | None = None
 # --------------------------------------------------------------------------- net
 
 
+_BIND_ALIASES = {"": "0.0.0.0", "all": "0.0.0.0", "any": "0.0.0.0", "*": "0.0.0.0",
+                 "local": "127.0.0.1", "localhost": "127.0.0.1", "loopback": "127.0.0.1"}
+
+
+def norm_bind(value: str) -> str:
+    """Listen address as NetX needs it: an IPv4 literal present on this host.
+
+    Accepts aliases (all/*, local/localhost). Raises ValueError with a reason.
+    """
+    v = _BIND_ALIASES.get(value.strip().lower(), value.strip())
+    try:
+        socket.inet_aton(v)
+        if v.count(".") != 3:
+            raise OSError
+    except OSError:
+        raise ValueError(f"not an IPv4 address: {value!r} (use 0.0.0.0 for all interfaces)")
+    if v != "0.0.0.0":
+        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        try:
+            s.bind((v, 0))
+        except OSError:
+            raise ValueError(f"{v} is not an address of this server")
+        finally:
+            s.close()
+    return v
+
+
 def port_free(port: int, host: str = "0.0.0.0") -> bool:
-    """True when nothing listens on `port` (checks the wildcard and loopback)."""
+    """True when nothing listens on `port` (checks the wildcard and loopback).
+
+    Only EADDRINUSE/EACCES mean "taken"; any other bind error is a bad address
+    and must not be reported as a busy port.
+    """
+    import errno
+
     for h in {host, "0.0.0.0", "127.0.0.1"}:
         s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         try:
             s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
             s.bind((h, port))
-        except OSError:
-            return False
+        except OSError as exc:
+            if exc.errno in (errno.EADDRINUSE, errno.EACCES):
+                return False
+            raise ValueError(f"cannot bind {h}:{port}: {exc}")
         finally:
             s.close()
     # Also catch a listener bound only to a specific address we did not test.
@@ -449,7 +484,19 @@ def cmd_env_export(a: argparse.Namespace) -> None:
 
 
 def cmd_port_free(a: argparse.Namespace) -> None:
-    sys.exit(0 if port_free(valid_port(a.port), a.host) else 1)
+    """exit 0 = free, 1 = in use, 3 = bad listen address."""
+    try:
+        free = port_free(valid_port(a.port), a.host)
+    except ValueError as exc:
+        die("bad_listen_address", str(exc), rc=3)
+    sys.exit(0 if free else 1)
+
+
+def cmd_norm_bind(a: argparse.Namespace) -> None:
+    try:
+        print(norm_bind(a.value))
+    except ValueError as exc:
+        die("bad_listen_address", str(exc))
 
 
 def cmd_valid_port(a: argparse.Namespace) -> None:
@@ -636,6 +683,7 @@ def main(argv: list[str] | None = None) -> None:
     s = sub.add_parser("env-export"); s.add_argument("file"); s.set_defaults(fn=cmd_env_export)
     s = sub.add_parser("port-free"); s.add_argument("port"); s.add_argument("--host", default="0.0.0.0")
     s.set_defaults(fn=cmd_port_free)
+    s = sub.add_parser("norm-bind"); s.add_argument("value"); s.set_defaults(fn=cmd_norm_bind)
     s = sub.add_parser("valid-port"); s.add_argument("port"); s.set_defaults(fn=cmd_valid_port)
     s = sub.add_parser("gen-secret"); s.add_argument("kind", choices=["fernet", "password"]); s.set_defaults(fn=cmd_gen_secret)
     s = sub.add_parser("build-url")
diff --git a/packaging/linux/netxctl b/packaging/linux/netxctl
index 3a4a2c6..d27d88e 100755
--- a/packaging/linux/netxctl
+++ b/packaging/linux/netxctl
@@ -287,8 +287,9 @@ cmd_set_port() {
 
 cmd_set_bind() {
   need_root set-bind; need_install
-  local h="${1:-}"
-  [[ -n "${h}" ]] || die "usage: netxctl set-bind <0.0.0.0|127.0.0.1|ip>"
+  local h
+  [[ -n "${1:-}" ]] || die "usage: netxctl set-bind <0.0.0.0|127.0.0.1|ip>"
+  h="$(netx_admin norm-bind -- "$1")" || exit 1
   local pairs=("NETX_HOST=${h}")
   # Same prerequisites NetX enforces for a non-loopback bind (security_bootstrap.py).
   if ! is_loopback "${h}"; then