diff --git a/src/app/Http/Controllers/API/V4/PolicyController.php b/src/app/Http/Controllers/API/V4/PolicyController.php
--- a/src/app/Http/Controllers/API/V4/PolicyController.php
+++ b/src/app/Http/Controllers/API/V4/PolicyController.php
@@ -19,8 +19,6 @@
     {
         $data = \request()->input();
 
-        list($local, $domainName) = explode('@', $data['recipient']);
-
         $request = new \App\Policy\Greylist\Request($data);
 
         $shouldDefer = $request->shouldDefer();
diff --git a/src/app/IP4Net.php b/src/app/IP4Net.php
--- a/src/app/IP4Net.php
+++ b/src/app/IP4Net.php
@@ -20,21 +20,12 @@
         'updated_at'
     ];
 
-    public static function getNet($ip, $mask = 32)
+    public static function getNet($ip)
     {
-        $query =  "
-            SELECT id FROM ip4nets
-            WHERE INET_ATON(net_number) <= INET_ATON(?)
-            AND INET_ATON(net_broadcast) >= INET_ATON(?)
-            ORDER BY INET_ATON(net_number), net_mask DESC LIMIT 1
-        ";
-
-        $results = DB::select($query, [$ip, $ip]);
-
-        if (sizeof($results) == 0) {
-            return null;
-        }
-
-        return \App\IP4Net::find($results[0]->id);
+        $where = 'INET_ATON(net_number) <= INET_ATON(?) and INET_ATON(net_broadcast) >= INET_ATON(?)';
+        return IP4Net::whereRaw($where, [$ip, $ip])
+            ->orderByRaw('INET_ATON(net_number), net_mask DESC')
+            ->limit(1)
+            ->first();
     }
 }
diff --git a/src/app/IP6Net.php b/src/app/IP6Net.php
--- a/src/app/IP6Net.php
+++ b/src/app/IP6Net.php
@@ -20,21 +20,12 @@
         'updated_at'
     ];
 
-    public static function getNet($ip, $mask = 128)
+    public static function getNet($ip)
     {
-        $query =  "
-            SELECT id FROM ip6nets
-            WHERE INET6_ATON(net_number) <= INET6_ATON(?)
-            AND INET6_ATON(net_broadcast) >= INET6_ATON(?)
-            ORDER BY INET6_ATON(net_number), net_mask DESC LIMIT 1
-        ";
-
-        $results = DB::select($query, [$ip, $ip]);
-
-        if (sizeof($results) == 0) {
-            return null;
-        }
-
-        return \App\IP6Net::find($results[0]->id);
+        $where = 'INET6_ATON(net_number) <= INET6_ATON(?) and INET6_ATON(net_broadcast) >= INET6_ATON(?)';
+        return IP6Net::whereRaw($where, [$ip, $ip])
+            ->orderByRaw('INET6_ATON(net_number), net_mask DESC')
+            ->limit(1)
+            ->first();
     }
 }
diff --git a/src/app/Policy/Greylist/Request.php b/src/app/Policy/Greylist/Request.php
--- a/src/app/Policy/Greylist/Request.php
+++ b/src/app/Policy/Greylist/Request.php
@@ -64,8 +64,6 @@
 
     public function shouldDefer()
     {
-        $deferIfPermit = true;
-
         list($this->netID, $this->netType) = \App\Utils::getNetFromAddress($this->request['client_address']);
 
         if (!$this->netID) {
@@ -124,7 +122,7 @@
                 if ($domain) {
                     $setting = Setting::where(
                         [
-                            'object_id' => $recipient->domain()->id,
+                            'object_id' => $domain->id,
                             'object_type' => \App\Domain::class,
                             'key' => 'greylist_enabled'
                         ]
@@ -228,8 +226,21 @@
             ->orderBy('updated_at')
             ->first();
 
-        if (!$connect) {
-            $connect = Connect::create(
+        $deferIfPermit = true;
+
+        if ($connect) {
+            $connect->connect_count += 1;
+
+            // TODO: The period of time for which the greylisting persists is configurable.
+            if ($connect->created_at < $this->timestamp->copy()->subMinutes(5)) {
+                $deferIfPermit = false;
+
+                $connect->greylisting = false;
+            }
+
+            $connect->save();
+        } else {
+            Connect::create(
                 [
                     'sender_local' => $this->senderLocal,
                     'sender_domain' => $this->senderDomain,
@@ -238,24 +249,12 @@
                     'recipient_hash' => $this->recipientHash,
                     'recipient_id' => $this->recipientID,
                     'recipient_type' => $this->recipientType,
-                    'connect_count' => 0,
                     'created_at' => $this->timestamp,
                     'updated_at' => $this->timestamp
                 ]
             );
         }
 
-        $connect->connect_count += 1;
-
-        // TODO: The period of time for which the greylisting persists is configurable.
-        if ($connect->created_at < $this->timestamp->copy()->subMinutes(5)) {
-            $deferIfPermit = false;
-
-            $connect->greylisting = false;
-        }
-
-        $connect->save();
-
         return $deferIfPermit;
     }
 
@@ -282,8 +281,6 @@
 
     private function recipientFromRequest()
     {
-        $recipient = null;
-
         $recipients = \App\Utils::findObjectsByRecipientAddress($this->request['recipient']);
 
         if (sizeof($recipients) > 1) {
diff --git a/src/app/Traits/UserConfigTrait.php b/src/app/Traits/UserConfigTrait.php
--- a/src/app/Traits/UserConfigTrait.php
+++ b/src/app/Traits/UserConfigTrait.php
@@ -2,6 +2,8 @@
 
 namespace App\Traits;
 
+use App\Policy\Greylist;
+
 trait UserConfigTrait
 {
     /**
@@ -13,7 +15,11 @@
 
         // TODO: Should we store the default value somewhere in config?
 
-        $config['greylisting'] = $this->getSetting('greylist_enabled') !== 'false';
+        $config['greylisting'] = Greylist\Setting::where('key', 'greylist_enabled')
+            ->where('object_id', $this->id)
+            ->where('object_type', \App\User::class)
+            ->where('value', 'false')
+            ->exists() ? false : true;
 
         return $config;
     }
@@ -31,7 +37,23 @@
 
         foreach ($config as $key => $value) {
             if ($key == 'greylisting') {
-                $this->setSetting('greylist_enabled', $value ? 'true' : 'false');
+                $setting_value = $value ? 'true' : 'false';
+                $setting = Greylist\Setting::where('key', 'greylist_enabled')
+                    ->where('object_id', $this->id)
+                    ->where('object_type', \App\User::class)
+                    ->first();
+
+                if (!$setting) {
+                    Greylist\Setting::create([
+                            'key' => 'greylist_enabled',
+                            'object_id' => $this->id,
+                            'object_type' => \App\User::class,
+                            'value' => $setting_value,
+                    ]);
+                } else {
+                    $setting->value = $setting_value;
+                    $setting->save();
+                }
             } else {
                 $errors[$key] = \trans('validation.invalid-config-parameter');
             }
diff --git a/src/app/Utils.php b/src/app/Utils.php
--- a/src/app/Utils.php
+++ b/src/app/Utils.php
@@ -46,28 +46,12 @@
     public static function countryForIP($ip)
     {
         if (strpos($ip, ':') === false) {
-            $query = "
-                SELECT country FROM ip4nets
-                WHERE INET_ATON(net_number) <= INET_ATON(?)
-                AND INET_ATON(net_broadcast) >= INET_ATON(?)
-                ORDER BY INET_ATON(net_number), net_mask DESC LIMIT 1
-            ";
+            $net = \App\IP4Net::getNet($ip);
         } else {
-            $query =  "
-                SELECT id FROM ip6nets
-                WHERE INET6_ATON(net_number) <= INET6_ATON(?)
-                AND INET6_ATON(net_broadcast) >= INET6_ATON(?)
-                ORDER BY INET6_ATON(net_number), net_mask DESC LIMIT 1
-            ";
+            $net = \App\IP6Net::getNet($ip);
         }
 
-        $nets = \Illuminate\Support\Facades\DB::select($query, [$ip, $ip]);
-
-        if (sizeof($nets) > 0) {
-            return $nets[0]->country;
-        }
-
-        return 'CH';
+        return $net && $net->country ? $net->country : 'CH';
     }
 
     /**
diff --git a/src/database/migrations/2021_08_25_120000_greylist_settings_migrate.php b/src/database/migrations/2021_08_25_120000_greylist_settings_migrate.php
new file mode 100644
--- /dev/null
+++ b/src/database/migrations/2021_08_25_120000_greylist_settings_migrate.php
@@ -0,0 +1,43 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Schema;
+
+// phpcs:ignore
+class GreylistSettingsMigrate extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        $settings = DB::table('user_settings')->where('key', 'greylist_enabled')->get();
+
+        foreach ($settings as $setting) {
+            DB::table('greylist_settings')->insert([
+                    'key' => $setting->key,
+                    'value' => $setting->value,
+                    'object_id' => $setting->user_id,
+                    'object_type' => \App\User::class,
+                    'created_at' => $setting->created_at,
+                    'updated_at' => $setting->updated_at,
+            ]);
+        }
+
+        DB::table('user_settings')->where('key', 'greylist_enabled')->delete();
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        // do nothing
+    }
+}
diff --git a/src/tests/Browser/Admin/UserTest.php b/src/tests/Browser/Admin/UserTest.php
--- a/src/tests/Browser/Admin/UserTest.php
+++ b/src/tests/Browser/Admin/UserTest.php
@@ -85,6 +85,7 @@
     public function testUserInfo(): void
     {
         $this->browse(function (Browser $browser) {
+            \App\Policy\Greylist\Setting::where('key', 'greylist_enabled')->delete();
             $jack = $this->getTestUser('jack@kolab.org');
             $page = new UserPage($jack->id);
 
@@ -197,7 +198,7 @@
             $wallet->save();
             $group = $this->getTestGroup('group-test@kolab.org');
             $group->assignToWallet($john->wallets->first());
-            $john->setSetting('greylist_enabled', null);
+            \App\Policy\Greylist\Setting::where('key', 'greylist_enabled')->delete();
 
             // Click the managed-by link on Jack's page
             $browser->click('@user-info #manager a')
@@ -322,7 +323,7 @@
             ]);
 
             $page = new UserPage($ned->id);
-            $ned->setSetting('greylist_enabled', 'false');
+            $ned->setConfig(['greylisting' => false]);
 
             $browser->click('@user-users tbody tr:nth-child(4) td:first-child a')
                 ->on($page);
diff --git a/src/tests/Browser/Reseller/UserTest.php b/src/tests/Browser/Reseller/UserTest.php
--- a/src/tests/Browser/Reseller/UserTest.php
+++ b/src/tests/Browser/Reseller/UserTest.php
@@ -175,6 +175,8 @@
      */
     public function testUserInfo2(): void
     {
+        \App\Policy\Greylist\Setting::where('key', 'greylist_enabled')->delete();
+
         $this->browse(function (Browser $browser) {
             $john = $this->getTestUser('john@kolab.org');
             $page = new UserPage($john->id);
@@ -288,6 +290,7 @@
         // Now we go to Ned's info page, he's a controller on John's wallet
         $this->browse(function (Browser $browser) {
             $ned = $this->getTestUser('ned@kolab.org');
+            $ned->setConfig(['greylisting' => false]);
             $page = new UserPage($ned->id);
 
             $browser->click('@user-users tbody tr:nth-child(4) td:first-child a')
@@ -358,6 +361,15 @@
                     $browser->assertElementsCount('table tbody tr', 0)
                         ->assertSeeIn('table tfoot tr td', 'There are no distribution lists in this account.');
                 });
+
+            // Assert Settings tab
+            $browser->assertSeeIn('@nav #tab-settings', 'Settings')
+                ->click('@nav #tab-settings')
+                ->whenAvailable('@user-settings form', function (Browser $browser) {
+                    $browser->assertElementsCount('.row', 1)
+                        ->assertSeeIn('.row:first-child label', 'Greylisting')
+                        ->assertSeeIn('.row:first-child .text-danger', 'disabled');
+                });
         });
     }
 
diff --git a/src/tests/Browser/UsersTest.php b/src/tests/Browser/UsersTest.php
--- a/src/tests/Browser/UsersTest.php
+++ b/src/tests/Browser/UsersTest.php
@@ -341,7 +341,7 @@
     public function testUserSettings(): void
     {
         $john = $this->getTestUser('john@kolab.org');
-        $john->setSetting('greylist_enabled', null);
+        \App\Policy\Greylist\Setting::where('key', 'greylist_enabled')->delete();
 
         $this->browse(function (Browser $browser) use ($john) {
             $browser->visit('/user/' . $john->id)
@@ -358,7 +358,7 @@
                 });
         });
 
-        $this->assertSame('false', $john->fresh()->getSetting('greylist_enabled'));
+        $this->assertFalse($john->getConfig()['greylisting']);
     }
 
     /**
diff --git a/src/tests/Feature/Controller/UsersTest.php b/src/tests/Feature/Controller/UsersTest.php
--- a/src/tests/Feature/Controller/UsersTest.php
+++ b/src/tests/Feature/Controller/UsersTest.php
@@ -6,6 +6,7 @@
 use App\Domain;
 use App\Http\Controllers\API\V4\UsersController;
 use App\Package;
+use App\Policy\Greylist;
 use App\Sku;
 use App\User;
 use App\Wallet;
@@ -66,7 +67,7 @@
         $wallet->discount()->dissociate();
         $wallet->settings()->whereIn('key', ['mollie_id', 'stripe_id'])->delete();
         $wallet->save();
-        $user->settings()->whereIn('key', ['greylist_enabled'])->delete();
+        Greylist\Setting::where('key', 'greylist_enabled')->delete();
         $user->status |= User::STATUS_IMAP_READY;
         $user->save();
 
@@ -475,7 +476,7 @@
         $jack = $this->getTestUser('jack@kolab.org');
         $john = $this->getTestUser('john@kolab.org');
 
-        $john->setSetting('greylist_enabled', null);
+        Greylist\Setting::where('key', 'greylist_enabled')->delete();
 
         // Test unknown user id
         $post = ['greylisting' => 1];
@@ -507,7 +508,7 @@
         $this->assertCount(1, $json['errors']);
         $this->assertSame('The requested configuration parameter is not supported.', $json['errors']['grey']);
 
-        $this->assertNull($john->fresh()->getSetting('greylist_enabled'));
+        $this->assertTrue($john->getConfig()['greylisting']);
 
         // Test some valid data
         $post = ['greylisting' => 1];
@@ -520,7 +521,7 @@
         $this->assertSame('success', $json['status']);
         $this->assertSame('User settings updated successfully.', $json['message']);
 
-        $this->assertSame('true', $john->fresh()->getSetting('greylist_enabled'));
+        $this->assertTrue($john->getConfig()['greylisting']);
 
         // Test some valid data
         $post = ['greylisting' => 0];
@@ -533,7 +534,7 @@
         $this->assertSame('success', $json['status']);
         $this->assertSame('User settings updated successfully.', $json['message']);
 
-        $this->assertSame('false', $john->fresh()->getSetting('greylist_enabled'));
+        $this->assertFalse($john->getConfig()['greylisting']);
     }
 
     /**
diff --git a/src/tests/Feature/UserTest.php b/src/tests/Feature/UserTest.php
--- a/src/tests/Feature/UserTest.php
+++ b/src/tests/Feature/UserTest.php
@@ -354,6 +354,34 @@
         $this->assertNotContains($domain->namespace, $domains);
     }
 
+    /**
+     * Test User::getConfig() and setConfig() methods
+     */
+    public function testConfigTrait(): void
+    {
+        $john = $this->getTestUser('john@kolab.org');
+        \App\Policy\Greylist\Setting::where('key', 'greylist_enabled')->delete();
+
+        $this->assertSame(['greylisting' => true], $john->getConfig());
+
+        $result = $john->setConfig(['greylisting' => false, 'unknown' => false]);
+
+        $this->assertSame(['greylisting' => false], $john->getConfig());
+
+        $setting = \App\Policy\Greylist\Setting::where('key', 'greylist_enabled')
+            ->where('object_id', $john->id)
+            ->where('object_type', User::class)
+            ->first();
+
+        $this->assertSame('false', $setting->value);
+
+        $result = $john->setConfig(['greylisting' => true]);
+
+        $this->assertSame(['greylisting' => true], $john->getConfig());
+
+        $this->assertSame('true', $setting->fresh()->value);
+    }
+
     /**
      * Test User::hasSku() method
      */