diff --git a/bin/webpack-dev-server.js b/bin/webpack-dev-server.js
index 26de7d4ba6..7c3456f5d3 100755
--- a/bin/webpack-dev-server.js
+++ b/bin/webpack-dev-server.js
@@ -15,7 +15,6 @@ const setupExitSignals = require('../lib/utils/setupExitSignals');
 const colors = require('../lib/utils/colors');
 const processOptions = require('../lib/utils/processOptions');
 const createLogger = require('../lib/utils/createLogger');
-const findPort = require('../lib/utils/findPort');
 const getVersions = require('../lib/utils/getVersions');
 const options = require('./options');
 
@@ -148,18 +147,11 @@ function startDevServer(config, options) {
       });
     });
   } else {
-    findPort(options.port)
-      .then((port) => {
-        options.port = port;
-        server.listen(options.port, options.host, (err) => {
-          if (err) {
-            throw err;
-          }
-        });
-      })
-      .catch((err) => {
+    server.listen(options.port, options.host, (err) => {
+      if (err) {
         throw err;
-      });
+      }
+    });
   }
 }
 
diff --git a/lib/utils/processOptions.js b/lib/utils/processOptions.js
index 23da69b430..ba224ed690 100644
--- a/lib/utils/processOptions.js
+++ b/lib/utils/processOptions.js
@@ -2,6 +2,7 @@
 
 const createConfig = require('./createConfig');
 const defaultPort = require('./defaultPort');
+const findPort = require('./findPort');
 
 function processOptions(config, argv, callback) {
   // processOptions {Promise}
@@ -23,7 +24,21 @@ function processOptions(config, argv, callback) {
   // we should use portfinder.
   const options = createConfig(config, argv, { port: defaultPort });
 
-  callback(config, options);
+  if (options.socket) {
+    callback(config, options);
+  } else {
+    findPort(options.port)
+      .then((port) => {
+        options.port = port;
+        callback(config, options);
+      })
+      .catch((err) => {
+        // eslint-disable-next-line no-console
+        console.error(err.stack || err);
+        // eslint-disable-next-line no-process-exit
+        process.exit(1);
+      });
+  }
 }
 
 module.exports = processOptions;
diff --git a/test/cli/cli.test.js b/test/cli/cli.test.js
index 4530b831ac..b22bc4a8b4 100644
--- a/test/cli/cli.test.js
+++ b/test/cli/cli.test.js
@@ -62,15 +62,36 @@ describe('CLI', () => {
     expect(stdout.includes('Project is running at')).toBe(true);
   });
 
-  it('--sockPath', async () => {
-    const { stdout } = await testBin('--sockPath /mysockPath');
-    expect(stdout.includes('http://localhost&sockPath=/mysockPath')).toBe(true);
+  it('--sockPath', (done) => {
+    testBin('--sockPath /mysockPath')
+      .then((output) => {
+        expect(
+          /http:\/\/localhost:[0-9]+&sockPath=\/mysockPath/.test(output.stdout)
+        ).toEqual(true);
+        done();
+      })
+      .catch(done);
+  });
+
+  it('unspecified port', (done) => {
+    testBin('')
+      .then((output) => {
+        expect(/http:\/\/localhost:[0-9]+/.test(output.stdout)).toEqual(true);
+        done();
+      })
+      .catch(done);
   });
 
-  it('--color', async () => {
-    const { stdout } = await testBin('--color');
-    // https://github.com/webpack/webpack-dev-server/blob/master/lib/utils/colors.js
-    expect(stdout.includes('\u001b[39m \u001b[90m｢wds｣\u001b[39m:')).toBe(true);
+  it('--color', (done) => {
+    testBin('--color')
+      .then((output) => {
+        // https://github.com/webpack/webpack-dev-server/blob/master/lib/utils/colors.js
+        expect(
+          output.stdout.includes('\u001b[39m \u001b[90m｢wds｣\u001b[39m:')
+        ).toEqual(true);
+        done();
+      })
+      .catch(done);
   });
 
   // The Unix socket to listen to (instead of a host).