diff --git a/docs/changelog/2026-06-10-rdp-guacd-handshake-fix.md b/docs/changelog/2026-06-10-rdp-guacd-handshake-fix.md
new file mode 100644
index 00000000..6763fb06
--- /dev/null
+++ b/docs/changelog/2026-06-10-rdp-guacd-handshake-fix.md
@@ -0,0 +1,30 @@
+# 2026-06-10 — RDP guacd 握手修复
+
+## 摘要
+
+修复浏览器 RDP 连接时 guacd 报 `Guacamole protocol violation`：由透明 TCP 桥接改为服务端完成 guacd 握手后再转发 WebSocket。
+
+## 动机
+
+`guacamole-common-js` 的 `WebSocketTunnel` 假定服务端（官方 Java servlet）向 guacd 发送 `select`/`connect` 等指令；Nexus 原先将浏览器 WS 字节原样转发到 guacd，导致协议错误。
+
+## 涉及文件
+
+- `server/infrastructure/guacamole/protocol.py` — 指令编解码、guacd RDP 握手
+- `server/infrastructure/guacamole/ws_tunnel.py` — 握手后 WS↔guacd 桥接，过滤内部 ping
+- `server/api/rdp.py` — 使用 DB 中 `rdp_hosts` 凭据握手，JWT 仍走路径
+- `tests/test_guacamole_protocol.py` — 协议单测
+
+## 迁移 / 重启
+
+- 无 DB 迁移
+- 需重启 API 容器（`deploy-production.sh`）
+
+## 验证
+
+```bash
+bash scripts/local_verify.sh
+python -m pytest tests/test_guacamole_protocol.py -q
+```
+
+生产：3389 页连接 → guacd 日志无 protocol violation → 画布显示桌面。
diff --git a/docs/reports/2026-06-10-rdp-guacd-handshake-deploy-verification.md b/docs/reports/2026-06-10-rdp-guacd-handshake-deploy-verification.md
new file mode 100644
index 00000000..3a1887f3
--- /dev/null
+++ b/docs/reports/2026-06-10-rdp-guacd-handshake-deploy-verification.md
@@ -0,0 +1,50 @@
+# 2026-06-10 RDP guacd 握手修复 — 生产验证
+
+## 变更
+
+- 服务端完成 guacd `select` → `connect` → `ready` 握手，再桥接 WebSocket
+- 凭据来自 `rdp_hosts` 表，不依赖 URL 中的 password
+
+## 部署
+
+- 主机 `/opt/nexus` 已同步新文件
+- `nexus-1panel.sh upgrade --no-backup` 重建镜像 `nexus-prod-nexus`
+- `/health` → ok
+
+## 验证（Agent 执行）
+
+### 1. guacd 直连握手（容器内 Python）
+
+```
+handshake 20.189.75.225 3389 azureuserwindwos guacd guacd 4822
+READY $da3288e0-2943-4186-b542-b00156251633
+```
+
+guacd 日志：
+
+```
+Creating new client for protocol "rdp"
+Connected to RDPDR 1.13 as client 0x0003
+```
+
+### 2. WebSocket 隧道
+
+```
+FIRST_MSG 0.,37.$f5b63cbd-2af9-4ee4-a714-37a7fbf1df9c;
+```
+
+首包为 Guacamole tunnel OPEN（空 opcode + connection id），符合 `guacamole-common-js` 预期。
+
+### 3. 结论
+
+- 原 `Guacamole protocol violation`（透明 TCP 桥接）已消除
+- RDP 目标 20.189.75.225:3389 可从 guacd 建立会话
+
+## 待用户终验
+
+浏览器：`https://api.synaglobal.vip/app/#/rdp` → 选择 `azurewin11` → 连接，应出现远程桌面画布。
+
+## 备注
+
+- 代码尚未 `git push`（仅主机热更新 + 镜像重建）；建议后续提交 `protocol.py` / `ws_tunnel.py` / `rdp.py`
+- RDP 用户名库中为 `azureuserwindwos`（若 Windows 实际用户不同需在前端编辑）
diff --git a/server/api/rdp.py b/server/api/rdp.py
index cf5ba4fa..b63d6062 100644
--- a/server/api/rdp.py
+++ b/server/api/rdp.py
@@ -4,15 +4,17 @@ from __future__ import annotations
 
 import logging
 from typing import Optional
+from urllib.parse import parse_qs, unquote
 
 from fastapi import APIRouter, Path, WebSocket, WebSocketDisconnect
 
 from server.config import settings
 from server.domain.models import Admin
+from server.infrastructure.database.crypto import decrypt_value
 from server.infrastructure.database.session import AsyncSessionLocal
 from server.infrastructure.database.admin_repo import AdminRepositoryImpl
 from server.infrastructure.database.rdp_host_repo import RdpHostRepositoryImpl
-from server.infrastructure.guacamole.tunnel import bridge_websocket_to_guacd
+from server.infrastructure.guacamole.ws_tunnel import run_guacamole_rdp_tunnel
 
 logger = logging.getLogger("nexus.rdp")
 
@@ -55,19 +57,35 @@ async def _verify_rdp_access_token(token: str) -> Optional[Admin]:
         return admin
 
 
+def _rdp_password_plain(enc: str) -> str:
+    plain = str(enc or "").strip()
+    if not plain:
+        return ""
+    try:
+        return decrypt_value(plain)
+    except Exception:
+        return ""
+
+
+def _parse_display_size(query_string: bytes) -> tuple[int, int]:
+    qs = parse_qs(query_string.decode("utf-8", errors="replace"))
+    try:
+        w = int(qs.get("width", ["1024"])[0])
+        h = int(qs.get("height", ["768"])[0])
+        if w > 0 and h > 0:
+            return w, h
+    except (TypeError, ValueError):
+        pass
+    return 1024, 768
+
+
 @router.websocket("/ws/rdp/hosts/{host_id}/tunnel/{access_token}")
 async def rdp_guacamole_ws(
     websocket: WebSocket,
     host_id: int = Path(...),
     access_token: str = Path(..., description="URL-encoded JWT (not query — Guacamole appends ?connect)"),
 ):
-    """Transparent Guacamole tunnel to guacd after JWT + RDP host lookup.
-
-    Token is in the path because guacamole-common-js ``Client.connect()`` always
-    appends ``?hostname=...`` to the tunnel URL; a ``?token=`` query would break JWT parsing.
-    """
-    from urllib.parse import unquote
-
+    """Guacamole WS tunnel: JWT auth, server-side guacd handshake, then relay."""
     token = unquote(access_token).strip()
     if not token:
         await websocket.close(code=4001, reason="Missing JWT token")
@@ -89,17 +107,46 @@ async def rdp_guacamole_ws(
             await websocket.close(code=4404, reason="RDP host not found")
             return
 
+        password = _rdp_password_plain(row.password)
+        if not password:
+            await websocket.close(code=4400, reason="RDP password not configured")
+            return
+
+        connect_params = {
+            k: v
+            for k, v in (
+                ("hostname", row.host.strip()),
+                ("port", str(row.port)),
+                ("username", row.username.strip()),
+                ("password", password),
+                ("security", "any"),
+                ("ignore-cert", "true"),
+                ("disable-wallpaper", "true"),
+                ("disable-theming", "true"),
+                ("enable-font-smoothing", "true"),
+                ("enable-full-window-drag", "false"),
+                ("enable-desktop-composition", "false"),
+                ("enable-menu-animations", "false"),
+            )
+            if v
+        }
+
+    width, height = _parse_display_size(websocket.scope.get("query_string", b""))
+
     await websocket.accept(subprotocol="guacamole")
     try:
-        await bridge_websocket_to_guacd(
+        await run_guacamole_rdp_tunnel(
             websocket,
             settings.GUACD_HOST,
             settings.GUACD_PORT,
+            connect_params,
+            width=width,
+            height=height,
         )
     except WebSocketDisconnect:
         pass
     except OSError as exc:
-        logger.warning("RDP guacd bridge failed host_id=%s: %s", host_id, exc)
+        logger.warning("RDP guacd tunnel failed host_id=%s: %s", host_id, exc)
         try:
             await websocket.close(code=1011, reason="guacd unreachable")
         except Exception:
diff --git a/server/infrastructure/guacamole/protocol.py b/server/infrastructure/guacamole/protocol.py
new file mode 100644
index 00000000..27216a75
--- /dev/null
+++ b/server/infrastructure/guacamole/protocol.py
@@ -0,0 +1,141 @@
+"""Guacamole protocol helpers (instruction encode/decode + guacd handshake)."""
+
+from __future__ import annotations
+
+import asyncio
+import logging
+import uuid
+from typing import Optional
+
+logger = logging.getLogger("nexus.guacamole.protocol")
+
+
+def encode_element(value: str) -> str:
+    s = value if value is not None else ""
+    return f"{len(s)}.{s}"
+
+
+def encode_instruction(opcode: str, *args: str) -> str:
+    parts = [encode_element(opcode)] + [encode_element(a) for a in args]
+    return ",".join(parts) + ";"
+
+
+def parse_instruction(message: str) -> tuple[str, list[str]]:
+    """Parse one complete instruction (without trailing semicolon)."""
+    elements: list[str] = []
+    i = 0
+    length = len(message)
+    while i < length:
+        dot = message.find(".", i)
+        if dot < 0:
+            raise ValueError(f"invalid guacamole instruction at {i}")
+        el_len = int(message[i:dot])
+        start = dot + 1
+        end = start + el_len
+        elements.append(message[start:end])
+        i = end
+        if i < length and message[i] == ",":
+            i += 1
+        else:
+            break
+    if not elements:
+        raise ValueError("empty guacamole instruction")
+    return elements[0], elements[1:]
+
+
+class GuacdStream:
+    """Buffered guacd TCP reader — one instruction per read()."""
+
+    def __init__(self, reader: asyncio.StreamReader):
+        self._reader = reader
+        self._buf = b""
+
+    async def read_instruction(self) -> tuple[str, list[str]]:
+        while True:
+            semi = self._buf.find(b";")
+            if semi >= 0:
+                raw = self._buf[:semi]
+                self._buf = self._buf[semi + 1 :]
+                msg = raw.decode("utf-8", errors="replace")
+                return parse_instruction(msg)
+            chunk = await self._reader.read(8192)
+            if not chunk:
+                raise ConnectionError("guacd closed during read")
+            self._buf += chunk
+
+    async def read_some(self) -> bytes:
+        """Read bytes for relay after handshake (buffered remainder first)."""
+        if self._buf:
+            data = self._buf
+            self._buf = b""
+            return data
+        return await self._reader.read(8192)
+
+
+def _param_for_arg(arg_name: str, params: dict[str, str]) -> str:
+    """Map guacd arg name to connection parameter value."""
+    normalized = arg_name.replace("_", "-").lower()
+    for key, value in params.items():
+        if key.replace("_", "-").lower() == normalized:
+            return value or ""
+    return ""
+
+
+async def guacd_rdp_handshake(
+    stream: GuacdStream,
+    writer: asyncio.StreamWriter,
+    params: dict[str, str],
+    *,
+    width: int = 1024,
+    height: int = 768,
+    dpi: int = 96,
+) -> str:
+    """Run guacd handshake for RDP; return connection id from ``ready``."""
+    writer.write(encode_instruction("select", "rdp").encode("utf-8"))
+    await writer.drain()
+
+    arg_names: list[str] = []
+    while True:
+        opcode, args = await stream.read_instruction()
+        if opcode == "args":
+            arg_names = list(args)
+            break
+        if opcode == "error":
+            raise RuntimeError(args[0] if args else "guacd error during args")
+        logger.warning("guacd unexpected during select: %s %s", opcode, args)
+
+    writer.write(encode_instruction("size", str(width), str(height), str(dpi)).encode("utf-8"))
+    await writer.drain()
+    writer.write(encode_instruction("audio").encode("utf-8"))
+    await writer.drain()
+    writer.write(encode_instruction("video").encode("utf-8"))
+    await writer.drain()
+
+    connect_values = [_param_for_arg(name, params) for name in arg_names]
+    writer.write(encode_instruction("connect", *connect_values).encode("utf-8"))
+    await writer.drain()
+
+    while True:
+        opcode, args = await stream.read_instruction()
+        if opcode == "ready":
+            if not args:
+                raise RuntimeError("guacd ready without connection id")
+            return args[0]
+        if opcode == "error":
+            raise RuntimeError(args[0] if args else "guacd connection failed")
+        logger.debug("guacd during handshake: %s %s", opcode, args)
+
+
+def tunnel_open_instruction(connection_id: Optional[str] = None) -> str:
+    """Empty opcode + UUID — tells guacamole-common-js the tunnel is OPEN."""
+    cid = connection_id or str(uuid.uuid4())
+    return encode_instruction("", cid)
+
+
+def is_internal_instruction(message: str) -> bool:
+    """True if message uses internal (empty) opcode — not for guacd."""
+    try:
+        opcode, _ = parse_instruction(message.rstrip(";"))
+        return opcode == ""
+    except ValueError:
+        return False
diff --git a/server/infrastructure/guacamole/ws_tunnel.py b/server/infrastructure/guacamole/ws_tunnel.py
new file mode 100644
index 00000000..39214752
--- /dev/null
+++ b/server/infrastructure/guacamole/ws_tunnel.py
@@ -0,0 +1,84 @@
+"""Guacamole WebSocket tunnel: handshake with guacd then relay (not raw TCP bridge)."""
+
+from __future__ import annotations
+
+import asyncio
+import logging
+
+from fastapi import WebSocket, WebSocketDisconnect
+
+from server.infrastructure.guacamole.protocol import (
+    GuacdStream,
+    guacd_rdp_handshake,
+    is_internal_instruction,
+    tunnel_open_instruction,
+)
+
+logger = logging.getLogger("nexus.guacamole.ws_tunnel")
+
+
+async def run_guacamole_rdp_tunnel(
+    websocket: WebSocket,
+    guacd_host: str,
+    guacd_port: int,
+    connect_params: dict[str, str],
+    *,
+    width: int = 1024,
+    height: int = 768,
+) -> None:
+    """Handshake with guacd using server-side credentials, then bridge WS ↔ guacd."""
+    reader, writer = await asyncio.open_connection(guacd_host, guacd_port)
+    stream = GuacdStream(reader)
+
+    try:
+        conn_id = await guacd_rdp_handshake(
+            stream, writer, connect_params, width=width, height=height,
+        )
+        await websocket.send_text(tunnel_open_instruction(conn_id))
+    except Exception as exc:
+        logger.warning("guacd handshake failed: %s", exc)
+        writer.close()
+        try:
+            await writer.wait_closed()
+        except Exception:
+            pass
+        await websocket.close(code=1011, reason=str(exc)[:120])
+        return
+
+    async def ws_to_guacd() -> None:
+        try:
+            while True:
+                data = await websocket.receive_text()
+                if is_internal_instruction(data):
+                    if "ping" in data:
+                        await websocket.send_text(data)
+                    continue
+                writer.write(data.encode("utf-8"))
+                await writer.drain()
+        except WebSocketDisconnect:
+            pass
+        except Exception as exc:
+            logger.debug("RDP WS→guacd ended: %s", exc)
+
+    async def guacd_to_ws() -> None:
+        try:
+            while True:
+                chunk = await stream.read_some()
+                if not chunk:
+                    break
+                await websocket.send_text(chunk.decode("utf-8", errors="replace"))
+        except Exception as exc:
+            logger.debug("RDP guacd→WS ended: %s", exc)
+
+    ws_task = asyncio.create_task(ws_to_guacd())
+    guacd_task = asyncio.create_task(guacd_to_ws())
+    try:
+        await asyncio.wait([ws_task, guacd_task], return_when=asyncio.FIRST_COMPLETED)
+    finally:
+        for task in (ws_task, guacd_task):
+            task.cancel()
+        writer.close()
+        try:
+            await writer.wait_closed()
+        except Exception:
+            pass
diff --git a/tests/test_guacamole_protocol.py b/tests/test_guacamole_protocol.py
new file mode 100644
index 00000000..50ac8f1b
--- /dev/null
+++ b/tests/test_guacamole_protocol.py
@@ -0,0 +1,32 @@
+"""Guacamole protocol encode/decode and internal opcode detection."""
+
+from server.infrastructure.guacamole.protocol import (
+    encode_instruction,
+    is_internal_instruction,
+    parse_instruction,
+    tunnel_open_instruction,
+)
+
+
+def test_encode_instruction():
+    assert encode_instruction("select", "rdp") == "6.select,3.rdp;"
+
+
+def test_parse_instruction_roundtrip():
+    raw = encode_instruction("connect", "host", "3389").rstrip(";")
+    opcode, args = parse_instruction(raw)
+    assert opcode == "connect"
+    assert args == ["host", "3389"]
+
+
+def test_tunnel_open_instruction():
+    msg = tunnel_open_instruction("abc-uuid")
+    assert is_internal_instruction(msg)
+    opcode, args = parse_instruction(msg.rstrip(";"))
+    assert opcode == ""
+    assert args == ["abc-uuid"]
+
+
+def test_is_internal_ping():
+    ping = encode_instruction("", "ping", "12345")
+    assert is_internal_instruction(ping)