diff --git a/src/listener.ts b/src/listener.ts
index 0e637cd..6022240 100644
--- a/src/listener.ts
+++ b/src/listener.ts
@@ -150,6 +150,7 @@ const responseViaResponseObject = async (
 export const getRequestListener = (
   fetchCallback: FetchCallback,
   options: {
+    hostname?: string
     errorHandler?: CustomErrorHandler
     overrideGlobalObjects?: boolean
   } = {}
@@ -173,7 +174,7 @@ export const getRequestListener = (
     try {
       // `fetchCallback()` requests a Request object, but global.Request is expensive to generate,
       // so generate a pseudo Request object with only the minimum required information.
-      req = newRequest(incoming)
+      req = newRequest(incoming, options.hostname)
 
       // Detect if request was aborted.
       outgoing.on('close', () => {
diff --git a/src/request.ts b/src/request.ts
index a8b7f65..3ec8116 100644
--- a/src/request.ts
+++ b/src/request.ts
@@ -130,11 +130,16 @@ const requestPrototype: Record<string | symbol, any> = {
 })
 Object.setPrototypeOf(requestPrototype, Request.prototype)
 
-export const newRequest = (incoming: IncomingMessage | Http2ServerRequest) => {
+export const newRequest = (
+  incoming: IncomingMessage | Http2ServerRequest,
+  defaultHostname?: string
+) => {
   const req = Object.create(requestPrototype)
   req[incomingKey] = incoming
 
-  const host = incoming instanceof Http2ServerRequest ? incoming.authority : incoming.headers.host
+  const host =
+    (incoming instanceof Http2ServerRequest ? incoming.authority : incoming.headers.host) ||
+    defaultHostname
   if (!host) {
     throw new RequestError('Missing host header')
   }
diff --git a/src/server.ts b/src/server.ts
index d1b3146..c02fcc8 100644
--- a/src/server.ts
+++ b/src/server.ts
@@ -6,6 +6,7 @@ import type { Options, ServerType } from './types'
 export const createAdaptorServer = (options: Options): ServerType => {
   const fetchCallback = options.fetch
   const requestListener = getRequestListener(fetchCallback, {
+    hostname: options.hostname,
     overrideGlobalObjects: options.overrideGlobalObjects,
   })
   // ts will complain about createServerHTTP and createServerHTTP2 not being callable, which works just fine
diff --git a/test/listener.test.ts b/test/listener.test.ts
index a1e6eeb..bf1527b 100644
--- a/test/listener.test.ts
+++ b/test/listener.test.ts
@@ -1,28 +1,69 @@
 import { createServer } from 'node:http'
 import request from 'supertest'
 import { getRequestListener } from '../src/listener'
-import { GlobalRequest, Request as LightweightRequest } from '../src/request'
+import { GlobalRequest, Request as LightweightRequest, RequestError } from '../src/request'
 import { GlobalResponse, Response as LightweightResponse } from '../src/response'
 
 describe('Invalid request', () => {
-  const requestListener = getRequestListener(jest.fn())
-  const server = createServer(async (req, res) => {
-    await requestListener(req, res)
+  describe('default error handler', () => {
+    const requestListener = getRequestListener(jest.fn())
+    const server = createServer(requestListener)
 
-    if (!res.writableEnded) {
-      res.writeHead(500, { 'Content-Type': 'text/plain' })
-      res.end('error handler did not return a response')
-    }
+    it('Should return server error for a request w/o host header', async () => {
+      const res = await request(server).get('/').set('Host', '').send()
+      expect(res.status).toBe(400)
+    })
+
+    it('Should return server error for a request invalid host header', async () => {
+      const res = await request(server).get('/').set('Host', 'a b').send()
+      expect(res.status).toBe(400)
+    })
   })
 
-  it('Should return server error for a request w/o host header', async () => {
-    const res = await request(server).get('/').set('Host', '').send()
-    expect(res.status).toBe(400)
+  describe('custom error handler', () => {
+    const requestListener = getRequestListener(jest.fn(), {
+      errorHandler: (e) => {
+        if (e instanceof RequestError) {
+          return new Response(e.message, { status: 400 })
+        }
+        else {
+          return new Response('unknown error', { status: 500 })
+        }
+      },
+    })
+    const server = createServer(requestListener)
+
+    it('Should return server error for a request w/o host header', async () => {
+      const res = await request(server).get('/').set('Host', '').send()
+      expect(res.status).toBe(400)
+    })
+
+    it('Should return server error for a request invalid host header', async () => {
+      const res = await request(server).get('/').set('Host', 'a b').send()
+      expect(res.status).toBe(400)
+    })
+
+    it('Should return server error for host header with path', async () => {
+      const res = await request(server).get('/').set('Host', 'a/b').send()
+      expect(res.status).toBe(400)
+    })
   })
 
-  it('Should return server error for a request invalid host header', async () => {
-    const res = await request(server).get('/').set('Host', 'a b').send()
-    expect(res.status).toBe(400)
+  describe('default hostname', () => {
+    const requestListener = getRequestListener(() => new Response('ok'), {
+      hostname: 'example.com',
+    })
+    const server = createServer(requestListener)
+
+    it('Should return 200 for a request w/o host header', async () => {
+      const res = await request(server).get('/').set('Host', '').send()
+      expect(res.status).toBe(200)
+    })
+
+    it('Should return server error for a request invalid host header', async () => {
+      const res = await request(server).get('/').set('Host', 'a b').send()
+      expect(res.status).toBe(400)
+    })
   })
 })