fix(server): Listen only to 127.0.0.1 by default (#2977)

Co-authored-by: Nihal Gonsalves <nihal@nihalgonsalves.com>
Co-authored-by: Anthony Fu <anthonyfu117@hotmail.com>

docs/config/index.md

@@ -328,8 +328,12 @@ export default async ({ command, mode }) => {
 ### server.host
 
 - **Type:** `string`
+- **Default:** `'127.0.0.1'`
 
-  Specify server hostname.
+  Specify which IP addresses the server should listen on.
+  Set this to `0.0.0.0` to listen on all addresses, including LAN and public addresses.
+
+  This can be set via the CLI using `--host 0.0.0.0` or `--host`.
 
 ### server.port
 

packages/vite/src/node/cli.ts

@@ -63,7 +63,7 @@ cli
 cli
   .command('[root]') // default command
   .alias('serve')
-  .option('--host <host>', `[string] specify hostname`)
+  .option('--host [host]', `[string] specify hostname`)
   .option('--port <port>', `[number] specify port`)
   .option('--https', `[boolean] use TLS + HTTP/2`)
   .option('--open [path]', `[boolean | string] open browser on startup`)

packages/vite/src/node/preview.ts

@@ -41,33 +41,48 @@ export async function preview(
   )
 
   const options = config.server || {}
-  const hostname = options.host || 'localhost'
+  let hostname: string | undefined
+  if (options.host === undefined || options.host === 'localhost') {
+    // Use a secure default
+    hostname = '127.0.0.1'
+  } else if (options.host === true) {
+    // The user probably passed --host in the CLI, without arguments
+    hostname = undefined // undefined typically means 0.0.0.0 or :: (listen on all IPs)
+  } else {
+    hostname = options.host as string
+  }
   const protocol = options.https ? 'https' : 'http'
   const logger = config.logger
   const base = config.base
 
-  httpServer.listen(port, () => {
+  httpServer.listen(port, hostname, () => {
     logger.info(
       chalk.cyan(`\n  vite v${require('vite/package.json').version}`) +
         chalk.green(` build preview server running at:\n`)
     )
-    const interfaces = os.networkInterfaces()
-    Object.keys(interfaces).forEach((key) =>
-      (interfaces[key] || [])
-        .filter((details) => details.family === 'IPv4')
-        .map((detail) => {
-          return {
-            type: detail.address.includes('127.0.0.1')
-              ? 'Local:   '
-              : 'Network: ',
-            host: detail.address.replace('127.0.0.1', hostname)
-          }
-        })
-        .forEach(({ type, host }) => {
-          const url = `${protocol}://${host}:${chalk.bold(port)}${base}`
-          logger.info(`  > ${type} ${chalk.cyan(url)}`)
-        })
-    )
+    if (hostname === '127.0.0.1') {
+      const url = `${protocol}://localhost:${chalk.bold(port)}${base}`
+      logger.info(`  > Local: ${chalk.cyan(url)}`)
+      logger.info(`  > Network: ${chalk.dim('use `--host` to expose')}`)
+    } else {
+      const interfaces = os.networkInterfaces()
+      Object.keys(interfaces).forEach((key) =>
+        (interfaces[key] || [])
+          .filter((details) => details.family === 'IPv4')
+          .map((detail) => {
+            return {
+              type: detail.address.includes('127.0.0.1')
+                ? 'Local:   '
+                : 'Network: ',
+              host: detail.address
+            }
+          })
+          .forEach(({ type, host }) => {
+            const url = `${protocol}://${host}:${chalk.bold(port)}${base}`
+            logger.info(`  > ${type} ${chalk.cyan(url)}`)
+          })
+      )
+    }
 
     if (options.open) {
       const path = typeof options.open === 'string' ? options.open : base

packages/vite/src/node/server/index.ts

@@ -53,7 +53,7 @@ import { ssrRewriteStacktrace } from '../ssr/ssrStacktrace'
 import { createMissingImporterRegisterFn } from '../optimizer/registerMissing'
 
 export interface ServerOptions {
-  host?: string
+  host?: string | boolean
   port?: number
   /**
    * Enable TLS + HTTP/2.
@@ -532,8 +532,17 @@ async function startServer(
 
   const options = server.config.server || {}
   let port = inlinePort || options.port || 3000
-  let hostname = options.host || 'localhost'
-  if (hostname === '0.0.0.0') hostname = 'localhost'
+  let hostname: string | undefined
+  if (options.host === undefined || options.host === 'localhost') {
+    // Use a secure default
+    hostname = '127.0.0.1'
+  } else if (options.host === true) {
+    // probably passed --host in the CLI, without arguments
+    hostname = undefined // undefined typically means 0.0.0.0 or :: (listen on all IPs)
+  } else {
+    hostname = options.host as string
+  }
+
   const protocol = options.https ? 'https' : 'http'
   const info = server.config.logger.info
   const base = server.config.base
@@ -546,7 +555,7 @@ async function startServer(
           reject(new Error(`Port ${port} is already in use`))
         } else {
           info(`Port ${port} is in use, trying another one...`)
-          httpServer.listen(++port)
+          httpServer.listen(++port, hostname)
         }
       } else {
         httpServer.removeListener('error', onError)
@@ -556,7 +565,7 @@ async function startServer(
 
     httpServer.on('error', onError)
 
-    httpServer.listen(port, options.host, () => {
+    httpServer.listen(port, hostname, () => {
       httpServer.removeListener('error', onError)
 
       info(
@@ -566,23 +575,30 @@ async function startServer(
           clear: !server.config.logger.hasWarned
         }
       )
-      const interfaces = os.networkInterfaces()
-      Object.keys(interfaces).forEach((key) =>
-        (interfaces[key] || [])
-          .filter((details) => details.family === 'IPv4')
-          .map((detail) => {
-            return {
-              type: detail.address.includes('127.0.0.1')
-                ? 'Local:   '
-                : 'Network: ',
-              host: detail.address.replace('127.0.0.1', hostname)
-            }
-          })
-          .forEach(({ type, host }) => {
-            const url = `${protocol}://${host}:${chalk.bold(port)}${base}`
-            info(`  > ${type} ${chalk.cyan(url)}`)
-          })
-      )
+
+      if (hostname === '127.0.0.1') {
+        const url = `${protocol}://localhost:${chalk.bold(port)}${base}`
+        info(`  > Local: ${chalk.cyan(url)}`)
+        info(`  > Network: ${chalk.dim('use `--host` to expose')}`)
+      } else {
+        const interfaces = os.networkInterfaces()
+        Object.keys(interfaces).forEach((key) =>
+          (interfaces[key] || [])
+            .filter((details) => details.family === 'IPv4')
+            .map((detail) => {
+              return {
+                type: detail.address.includes('127.0.0.1')
+                  ? 'Local:   '
+                  : 'Network: ',
+                host: detail.address
+              }
+            })
+            .forEach(({ type, host }) => {
+              const url = `${protocol}://${host}:${chalk.bold(port)}${base}`
+              info(`  > ${type} ${chalk.cyan(url)}`)
+            })
+        )
+      }
 
       // @ts-ignore
       if (global.__vite_start_time) {

scripts/jestPerTestSetup.ts

@@ -73,7 +73,8 @@ beforeAll(async () => {
             // misses change events, so enforce polling for consistency
             usePolling: true,
             interval: 100
-          }
+          },
+          host: true
         },
         build: {
           // skip transpilation and dynamic import polyfills during tests to