diff --git a/app/Server/Http/Controllers/TunnelMessageController.php b/app/Server/Http/Controllers/TunnelMessageController.php
index a2635e5..f3e107f 100644
--- a/app/Server/Http/Controllers/TunnelMessageController.php
+++ b/app/Server/Http/Controllers/TunnelMessageController.php
@@ -70,11 +70,9 @@ class TunnelMessageController extends Controller
 
     protected function detectSubdomain(Request $request): ?string
     {
-        if (substr_count($request->header('Host'), '.') === 1) {
-            return null;
-        }
+        $serverHost = $this->detectServerHost($request);
 
-        $subdomain = Str::before($request->header('Host'), '.');
+        $subdomain = Str::before($request->header('Host'), '.'.$serverHost);
 
         return $subdomain === $request->header('Host') ? null : $subdomain;
     }
diff --git a/app/Server/SubdomainRepository/DatabaseSubdomainRepository.php b/app/Server/SubdomainRepository/DatabaseSubdomainRepository.php
index d540eeb..eaf3d00 100644
--- a/app/Server/SubdomainRepository/DatabaseSubdomainRepository.php
+++ b/app/Server/SubdomainRepository/DatabaseSubdomainRepository.php
@@ -135,7 +135,7 @@ class DatabaseSubdomainRepository implements SubdomainRepository
     {
         $deferred = new Deferred();
 
-        $this->database->query('DELETE FROM subdomains WHERE id = :id AND user_id = :user_id', [
+        $this->database->query('DELETE FROM subdomains WHERE (id = :id OR subdomain = :id) AND user_id = :user_id', [
             'id' => $subdomainId,
             'user_id' => $userId,
         ])
diff --git a/app/Server/UserRepository/DatabaseUserRepository.php b/app/Server/UserRepository/DatabaseUserRepository.php
index 62ce315..8f03031 100644
--- a/app/Server/UserRepository/DatabaseUserRepository.php
+++ b/app/Server/UserRepository/DatabaseUserRepository.php
@@ -150,15 +150,38 @@ class DatabaseUserRepository implements UserRepository
     {
         $deferred = new Deferred();
 
-        $this->database->query("
+        $this->getUserByToken($data['auth_token'])
+            ->then(function ($existingUser) use ($data, $deferred) {
+                if (is_null($existingUser)) {
+                    $this->database->query("
             INSERT INTO users (name, auth_token, can_specify_subdomains, can_specify_domains, can_share_tcp_ports, max_connections, created_at)
             VALUES (:name, :auth_token, :can_specify_subdomains, :can_specify_domains, :can_share_tcp_ports, :max_connections, DATETIME('now'))
         ", $data)
-            ->then(function (Result $result) use ($deferred) {
-                $this->database->query('SELECT * FROM users WHERE id = :id', ['id' => $result->insertId])
-                    ->then(function (Result $result) use ($deferred) {
-                        $deferred->resolve($result->rows[0]);
-                    });
+                        ->then(function (Result $result) use ($deferred) {
+                            $this->database->query('SELECT * FROM users WHERE id = :id', ['id' => $result->insertId])
+                                ->then(function (Result $result) use ($deferred) {
+                                    $deferred->resolve($result->rows[0]);
+                                });
+                        });
+                } else {
+                    $this->database->query('
+            UPDATE users
+            SET
+                name = :name,
+                can_specify_subdomains = :can_specify_subdomains,
+                can_specify_domains = :can_specify_domains,
+                can_share_tcp_ports = :can_share_tcp_ports,
+                max_connections = :max_connections
+            WHERE
+                auth_token = :auth_token
+        ', $data)
+                        ->then(function (Result $result) use ($existingUser, $deferred) {
+                            $this->database->query('SELECT * FROM users WHERE id = :id', ['id' => $existingUser['id']])
+                                ->then(function (Result $result) use ($deferred) {
+                                    $deferred->resolve($result->rows[0]);
+                                });
+                        });
+                }
             });
 
         return $deferred->promise();
diff --git a/tests/Feature/Server/ApiTest.php b/tests/Feature/Server/ApiTest.php
index 879963e..9026bc2 100644
--- a/tests/Feature/Server/ApiTest.php
+++ b/tests/Feature/Server/ApiTest.php
@@ -65,6 +65,97 @@ class ApiTest extends TestCase
         $this->assertSame([], $users[0]->sites);
     }
 
+    /** @test */
+    public function it_can_specify_a_token_when_creating_a_user()
+    {
+        /** @var Response $response */
+        $this->await($this->browser->post('http://127.0.0.1:8080/api/users', [
+            'Host' => 'expose.localhost',
+            'Authorization' => base64_encode('username:secret'),
+            'Content-Type' => 'application/json',
+        ], json_encode([
+            'name' => 'Marcel',
+            'token' => 'my-token',
+        ])));
+
+        /** @var Response $response */
+        $response = $this->await($this->browser->get('http://127.0.0.1:8080/api/users', [
+            'Host' => 'expose.localhost',
+            'Authorization' => base64_encode('username:secret'),
+            'Content-Type' => 'application/json',
+        ]));
+
+        $body = json_decode($response->getBody()->getContents());
+        $users = $body->paginated->users;
+
+        $this->assertCount(1, $users);
+        $this->assertSame('Marcel', $users[0]->name);
+        $this->assertSame('my-token', $users[0]->auth_token);
+        $this->assertSame([], $users[0]->sites);
+    }
+
+    /** @test */
+    public function it_updates_users_instead_of_creating_new_ones()
+    {
+        /** @var Response $response */
+        $this->await($this->browser->post('http://127.0.0.1:8080/api/users', [
+            'Host' => 'expose.localhost',
+            'Authorization' => base64_encode('username:secret'),
+            'Content-Type' => 'application/json',
+        ], json_encode([
+            'name' => 'Marcel',
+            'token' => 'my-token',
+        ])));
+
+        /** @var Response $response */
+        $response = $this->await($this->browser->get('http://127.0.0.1:8080/api/users', [
+            'Host' => 'expose.localhost',
+            'Authorization' => base64_encode('username:secret'),
+            'Content-Type' => 'application/json',
+        ]));
+
+        $body = json_decode($response->getBody()->getContents());
+        $users = $body->paginated->users;
+
+        $this->assertCount(1, $users);
+        $this->assertSame('Marcel', $users[0]->name);
+        $this->assertSame('my-token', $users[0]->auth_token);
+        $this->assertSame(0, $users[0]->can_specify_subdomains);
+        $this->assertSame(0, $users[0]->can_specify_domains);
+        $this->assertSame(0, $users[0]->can_share_tcp_ports);
+        $this->assertSame([], $users[0]->sites);
+
+        $this->await($this->browser->post('http://127.0.0.1:8080/api/users', [
+            'Host' => 'expose.localhost',
+            'Authorization' => base64_encode('username:secret'),
+            'Content-Type' => 'application/json',
+        ], json_encode([
+            'name' => 'Marcel Changed',
+            'token' => 'my-token',
+            'can_specify_subdomains' => 1,
+            'can_specify_domains' => 1,
+            'can_share_tcp_ports' => 1,
+        ])));
+
+        /** @var Response $response */
+        $response = $this->await($this->browser->get('http://127.0.0.1:8080/api/users', [
+            'Host' => 'expose.localhost',
+            'Authorization' => base64_encode('username:secret'),
+            'Content-Type' => 'application/json',
+        ]));
+
+        $body = json_decode($response->getBody()->getContents());
+        $users = $body->paginated->users;
+
+        $this->assertCount(1, $users);
+        $this->assertSame('Marcel Changed', $users[0]->name);
+        $this->assertSame('my-token', $users[0]->auth_token);
+        $this->assertSame(1, $users[0]->can_specify_subdomains);
+        $this->assertSame(1, $users[0]->can_specify_domains);
+        $this->assertSame(1, $users[0]->can_share_tcp_ports);
+        $this->assertSame([], $users[0]->sites);
+    }
+
     /** @test */
     public function it_can_specify_tokens_when_creating_a_user()
     {
@@ -288,6 +379,51 @@ class ApiTest extends TestCase
         $this->assertCount(0, $subdomains);
     }
 
+    /** @test */
+    public function it_can_delete_subdomains_by_name()
+    {
+        /** @var Response $response */
+        $response = $this->await($this->browser->post('http://127.0.0.1:8080/api/users', [
+            'Host' => 'expose.localhost',
+            'Authorization' => base64_encode('username:secret'),
+            'Content-Type' => 'application/json',
+        ], json_encode([
+            'name' => 'Marcel',
+            'can_specify_subdomains' => 1,
+        ])));
+
+        $user = json_decode($response->getBody()->getContents())->user;
+
+        $response = $this->await($this->browser->post('http://127.0.0.1:8080/api/subdomains', [
+            'Host' => 'expose.localhost',
+            'Authorization' => base64_encode('username:secret'),
+            'Content-Type' => 'application/json',
+        ], json_encode([
+            'subdomain' => 'reserved',
+            'auth_token' => $user->auth_token,
+        ])));
+
+        $this->await($this->browser->delete('http://127.0.0.1:8080/api/subdomains/reserved', [
+            'Host' => 'expose.localhost',
+            'Authorization' => base64_encode('username:secret'),
+            'Content-Type' => 'application/json',
+        ], json_encode([
+            'auth_token' => $user->auth_token,
+        ])));
+
+        /** @var Response $response */
+        $response = $this->await($this->browser->get('http://127.0.0.1:8080/api/users/1', [
+            'Host' => 'expose.localhost',
+            'Authorization' => base64_encode('username:secret'),
+            'Content-Type' => 'application/json',
+        ]));
+
+        $body = json_decode($response->getBody()->getContents());
+        $subdomains = $body->subdomains;
+
+        $this->assertCount(0, $subdomains);
+    }
+
     /** @test */
     public function it_can_not_reserve_an_already_reserved_subdomain()
     {
diff --git a/tests/Feature/Server/TunnelTest.php b/tests/Feature/Server/TunnelTest.php
index 0caefa3..20b2fdc 100644
--- a/tests/Feature/Server/TunnelTest.php
+++ b/tests/Feature/Server/TunnelTest.php
@@ -64,6 +64,17 @@ class TunnelTest extends TestCase
         ]));
     }
 
+    /** @test */
+    public function it_returns_404_for_non_existing_clients_on_custom_hosts()
+    {
+        $this->expectException(ResponseException::class);
+        $this->expectExceptionMessage(404);
+
+        $this->await($this->browser->get('http://127.0.0.1:8080/', [
+            'Host' => 'tunnel.share.beyondco.de',
+        ]));
+    }
+
     /** @test */
     public function it_sends_incoming_requests_to_the_connected_client()
     {
@@ -91,6 +102,33 @@ class TunnelTest extends TestCase
         $this->assertSame('Hello World!', $response->getBody()->getContents());
     }
 
+    /** @test */
+    public function it_sends_incoming_requests_to_the_connected_client_on_custom_hosts()
+    {
+        $this->app['config']['expose.admin.validate_auth_tokens'] = false;
+
+        $this->createTestHttpServer();
+
+        $this->app['config']['expose.admin.validate_auth_tokens'] = false;
+
+        /**
+         * We create an expose client that connects to our server and shares
+         * the created test HTTP server.
+         */
+        $client = $this->createClient();
+        $this->await($client->connectToServer('127.0.0.1:8085', 'tunnel', 'share.beyondco.de'));
+
+        /**
+         * Once the client is connected, we perform a GET request on the
+         * created tunnel.
+         */
+        $response = $this->await($this->browser->get('http://127.0.0.1:8080/', [
+            'Host' => 'tunnel.share.beyondco.de',
+        ]));
+
+        $this->assertSame('Hello World!', $response->getBody()->getContents());
+    }
+
     /** @test */
     public function it_sends_incoming_requests_to_the_connected_client_via_tcp()
     {