diff --git a/openwisp_radius/api/serializers.py b/openwisp_radius/api/serializers.py
index 34dafe74..3660b217 100644
--- a/openwisp_radius/api/serializers.py
+++ b/openwisp_radius/api/serializers.py
@@ -120,8 +120,6 @@ class RadiusPostAuthSerializer(serializers.ModelSerializer):
         allow_blank=True,
         style={'input_type': 'password'},
     )
-    called_station_id = serializers.CharField(required=False, allow_blank=True)
-    calling_station_id = serializers.CharField(required=False, allow_blank=True)
 
     def validate(self, data):
         # do not save correct passwords in clear text
diff --git a/openwisp_radius/base/models.py b/openwisp_radius/base/models.py
index a27d9c63..df7d62ee 100644
--- a/openwisp_radius/base/models.py
+++ b/openwisp_radius/base/models.py
@@ -434,7 +434,7 @@ class AbstractRadiusAccounting(OrgMixin, models.Model):
     )
     called_station_id = models.CharField(
         verbose_name=_('called station ID'),
-        max_length=50,
+        max_length=253,
         db_column='calledstationid',
         db_index=True,
         blank=True,
@@ -442,7 +442,7 @@ class AbstractRadiusAccounting(OrgMixin, models.Model):
     )
     calling_station_id = models.CharField(
         verbose_name=_('calling station ID'),
-        max_length=50,
+        max_length=253,
         db_column='callingstationid',
         db_index=True,
         blank=True,
@@ -791,14 +791,14 @@ class AbstractRadiusPostAuth(OrgMixin, UUIDModel):
     reply = models.CharField(verbose_name=_('reply'), max_length=32)
     called_station_id = models.CharField(
         verbose_name=_('called station ID'),
-        max_length=50,
+        max_length=253,
         db_column='calledstationid',
         blank=True,
         null=True,
     )
     calling_station_id = models.CharField(
         verbose_name=_('calling station ID'),
-        max_length=50,
+        max_length=253,
         db_column='callingstationid',
         blank=True,
         null=True,
diff --git a/openwisp_radius/migrations/0039_alter_radiusaccounting_called_station_id_and_more.py b/openwisp_radius/migrations/0039_alter_radiusaccounting_called_station_id_and_more.py
new file mode 100644
index 00000000..09a1044f
--- /dev/null
+++ b/openwisp_radius/migrations/0039_alter_radiusaccounting_called_station_id_and_more.py
@@ -0,0 +1,58 @@
+# Generated by Django 4.2.17 on 2024-12-23 15:24
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("openwisp_radius", "0038_clean_fallbackfields"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="radiusaccounting",
+            name="called_station_id",
+            field=models.CharField(
+                blank=True,
+                db_column="calledstationid",
+                db_index=True,
+                max_length=253,
+                null=True,
+                verbose_name="called station ID",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="radiusaccounting",
+            name="calling_station_id",
+            field=models.CharField(
+                blank=True,
+                db_column="callingstationid",
+                db_index=True,
+                max_length=253,
+                null=True,
+                verbose_name="calling station ID",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="radiuspostauth",
+            name="called_station_id",
+            field=models.CharField(
+                blank=True,
+                db_column="calledstationid",
+                max_length=253,
+                null=True,
+                verbose_name="called station ID",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="radiuspostauth",
+            name="calling_station_id",
+            field=models.CharField(
+                blank=True,
+                db_column="callingstationid",
+                max_length=253,
+                null=True,
+                verbose_name="calling station ID",
+            ),
+        ),
+    ]
diff --git a/openwisp_radius/tests/test_api/test_freeradius_api.py b/openwisp_radius/tests/test_api/test_freeradius_api.py
index 6616e42d..cbc6ef68 100644
--- a/openwisp_radius/tests/test_api/test_freeradius_api.py
+++ b/openwisp_radius/tests/test_api/test_freeradius_api.py
@@ -298,6 +298,25 @@ def test_postauth_400(self):
         self.assertEqual(RadiusPostAuth.objects.all().count(), 0)
         self.assertEqual(response.status_code, 400)
 
+    def test_postauth_station_id_max_length_253_exceed_400(self):
+        params = {
+            'called_station_id': 'C0-4A-00-EE-D1-0D:' + 'A' * 253,
+            'calling_station_id': '00:26:b9:20:5f:10' + 'A' * 253,
+        }
+        params = self._get_postauth_params(**params)
+        response = self.client.post(
+            reverse('radius:postauth'), params, HTTP_AUTHORIZATION=self.auth_header
+        )
+        self.assertEqual(response.status_code, 400)
+        self.assertEqual(
+            response.data['called_station_id'][0],
+            'Ensure this field has no more than 253 characters.',
+        )
+        self.assertEqual(
+            response.data['calling_station_id'][0],
+            'Ensure this field has no more than 253 characters.',
+        )
+
     @capture_any_output()
     def test_postauth_no_token_403(self):
         response = self.client.post(reverse('radius:postauth'), {'username': 'tester'})
diff --git a/tests/openwisp2/sample_radius/migrations/0030_alter_radiusaccounting_called_station_id_and_more.py b/tests/openwisp2/sample_radius/migrations/0030_alter_radiusaccounting_called_station_id_and_more.py
new file mode 100644
index 00000000..19a4dd0d
--- /dev/null
+++ b/tests/openwisp2/sample_radius/migrations/0030_alter_radiusaccounting_called_station_id_and_more.py
@@ -0,0 +1,61 @@
+# Generated by Django 4.2.17 on 2025-01-08 15:05
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        (
+            "sample_radius",
+            "0029_alter_organizationradiussettings_allowed_mobile_prefixes_and_more",
+        ),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="radiusaccounting",
+            name="called_station_id",
+            field=models.CharField(
+                blank=True,
+                db_column="calledstationid",
+                db_index=True,
+                max_length=253,
+                null=True,
+                verbose_name="called station ID",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="radiusaccounting",
+            name="calling_station_id",
+            field=models.CharField(
+                blank=True,
+                db_column="callingstationid",
+                db_index=True,
+                max_length=253,
+                null=True,
+                verbose_name="calling station ID",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="radiuspostauth",
+            name="called_station_id",
+            field=models.CharField(
+                blank=True,
+                db_column="calledstationid",
+                max_length=253,
+                null=True,
+                verbose_name="called station ID",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="radiuspostauth",
+            name="calling_station_id",
+            field=models.CharField(
+                blank=True,
+                db_column="callingstationid",
+                max_length=253,
+                null=True,
+                verbose_name="calling station ID",
+            ),
+        ),
+    ]