diff --git a/backend/internal/model/model.go b/backend/internal/model/model.go
index faf5b92..0be5ac7 100644
--- a/backend/internal/model/model.go
+++ b/backend/internal/model/model.go
@@ -41,6 +41,7 @@ type Instance struct {
 	AccessMode    AccessMode `json:"access_mode"`   // open | whitelist
 	AllowNetworks []string   `json:"allow_networks"` // 实例级白名单 CIDR 列表
 	AuthMode      AuthMode   `json:"auth_mode"`     // cert | cert+password
+	PublicHost    string     `json:"public_host"`    // 公网域名/IP,生成 .ovpn 时优先用它;空则用下载时前端传入的 host
 	Status        string     `json:"status"`        // running/stopped/error
 	PID           int        `json:"pid"`
 	CreatedAt     time.Time  `json:"created_at"`
diff --git a/backend/internal/service/service.go b/backend/internal/service/service.go
index 8f0f40c..52fcd3c 100644
--- a/backend/internal/service/service.go
+++ b/backend/internal/service/service.go
@@ -400,7 +400,8 @@ func (s *Service) CreateUser(u model.VPNUser) (*model.VPNUser, error) {
 	return &u, nil
 }
 
-// GenerateOVPN 下载/重新生成 .ovpn，remoteHost 由前端传入。
+// GenerateOVPN 下载/重新生成 .ovpn。
+// remoteHost 优先级:Instance.PublicHost > 传入的 remoteHost > "vpn.example.com"。
 func (s *Service) GenerateOVPN(userID, remoteHost string) (string, error) {
 	u, err := s.Store.GetUser(userID)
 	if err != nil {
@@ -410,7 +411,11 @@ func (s *Service) GenerateOVPN(userID, remoteHost string) (string, error) {
 	if err != nil {
 		return "", err
 	}
-	return s.Ovm.GenerateClientOVPNFor(u, in, remoteHost)
+	host := in.PublicHost
+	if host == "" {
+		host = remoteHost
+	}
+	return s.Ovm.GenerateClientOVPNFor(u, in, host)
 }
 
 // RevokeUser 吊销用户：禁用 + 标记。
diff --git a/frontend/src/views/Instances.vue b/frontend/src/views/Instances.vue
index 8d9e79c..7129cd5 100644
--- a/frontend/src/views/Instances.vue
+++ b/frontend/src/views/Instances.vue
@@ -12,6 +12,12 @@
       <el-table-column prop="proto" label="协议" width="80" />
       <el-table-column prop="dev" label="设备" width="80" />
       <el-table-column prop="subnet" label="子网" />
+      <el-table-column prop="public_host" label="公网地址">
+        <template #default="{row}">
+          <span v-if="row.public_host" style="font-family:monospace">{{ row.public_host }}</span>
+          <span v-else class="muted">未配置</span>
+        </template>
+      </el-table-column>
       <el-table-column label="访问控制" width="110">
         <template #default="{row}">
           <el-tag :type="row.access_mode==='whitelist'?'warning':'info'" size="small">
@@ -53,6 +59,12 @@
           <el-select v-model="form.dev"><el-option label="tun" value="tun"/><el-option label="tap" value="tap"/></el-select>
         </el-form-item>
         <el-form-item label="子网"><el-input v-model="form.subnet" placeholder="10.8.0.0/24"/></el-form-item>
+        <el-form-item label="公网地址">
+          <el-input v-model="form.public_host" placeholder="vpn.example.com 或 203.0.113.10" />
+          <div class="muted" style="margin-top:4px">
+            客户端连接时用的服务端地址。<b>留空</b>则下载 .ovpn 时手动输入;<b>填写</b>则所有用户下载的 .ovpn 自动用此地址,无需修改。
+          </div>
+        </el-form-item>
         <el-form-item label="加密">
           <el-select v-model="form.cipher"><el-option label="AES-256-GCM" value="AES-256-GCM"/><el-option label="AES-128-GCM" value="AES-128-GCM"/><el-option label="CHACHA20-POLY1305" value="CHACHA20-POLY1305"/></el-select>
         </el-form-item>
@@ -103,7 +115,7 @@ const router = useRouter()
 
 async function load() { list.value = await Inst.list() }
 function openCreate() {
-  Object.assign(form, { name:'', port:1194, proto:'udp', dev:'tun', subnet:'10.8.0.0/24', cipher:'AES-256-GCM', auth_digest:'SHA256', push_dns:'', push_routes:'', extra:'', access_mode:'open', allow_networks:[], id:'' })
+  Object.assign(form, { name:'', port:1194, proto:'udp', dev:'tun', subnet:'10.8.0.0/24', cipher:'AES-256-GCM', auth_digest:'SHA256', push_dns:'', push_routes:'', extra:'', access_mode:'open', allow_networks:[], public_host:'', id:'' })
   dlg.value = true
 }
 function openEdit(row) {
diff --git a/frontend/src/views/Users.vue b/frontend/src/views/Users.vue
index 8c4af33..2afd58a 100644
--- a/frontend/src/views/Users.vue
+++ b/frontend/src/views/Users.vue
@@ -7,7 +7,7 @@
           <el-option v-for="i in instances" :key="i.id" :value="i.id" :label="`${i.name} (${i.proto}/${i.port})`" />
         </el-select>
       </el-col>
-      <el-col :span="6"><el-input v-model="host" placeholder="客户端连接的远端域名/IP" /></el-col>
+      <el-col :span="6"><el-input v-model="host" placeholder="可选: 覆盖实例公网地址" /></el-col>
       <el-col :span="4"><el-button @click="loadUsers">刷新</el-button></el-col>
       <el-col :span="6" style="text-align:right">
         <el-button type="primary" :disabled="!instanceId" @click="openCreate"><el-icon><Plus /></el-icon>新建用户</el-button>