diff --git a/src/pyfreeradius.py b/src/pyfreeradius.py
index f7281ee..8dcb3ee 100644
--- a/src/pyfreeradius.py
+++ b/src/pyfreeradius.py
@@ -1,6 +1,6 @@
 from abc import ABC, abstractmethod
 from contextlib import contextmanager
-from pydantic import BaseModel, IPvAnyAddress, StringConstraints, Field, model_validator
+from pydantic import BaseModel, StringConstraints, Field, model_validator
 from typing import List
 from typing_extensions import Annotated
 
@@ -99,7 +99,7 @@ def check_fields_on_init(self):
 
 
 class Nas(BaseModel):
-    nasname: IPvAnyAddress
+    nasname: Annotated[str, StringConstraints(min_length=1)]
     shortname: Annotated[str, StringConstraints(min_length=1)]
     secret: Annotated[str, StringConstraints(min_length=1)]
 
@@ -348,10 +348,10 @@ class NasRepository(BaseRepository):
     def __init__(self, db_connection, db_tables: RadTables):
         super().__init__(db_connection, db_tables)
 
-    def exists(self, nasname: IPvAnyAddress) -> bool:
+    def exists(self, nasname: str) -> bool:
         with self._db_cursor() as db_cursor:
             sql = f"SELECT COUNT(DISTINCT nasname) FROM {self.nas} WHERE nasname = %s"
-            db_cursor.execute(sql, (str(nasname),))
+            db_cursor.execute(sql, (nasname,))
             (count,) = db_cursor.fetchone()
             return count > 0
 
@@ -362,7 +362,7 @@ def find_all_nasnames(self) -> List[str]:
             nasnames = [nasname for nasname, in db_cursor.fetchall()]
             return nasnames
 
-    def find_nasnames(self, from_nasname: IPvAnyAddress = None) -> List[str]:
+    def find_nasnames(self, from_nasname: str = None) -> List[str]:
         if not from_nasname:
             return self._find_first_nasnames()
         return self._find_next_nasnames(from_nasname)
@@ -375,29 +375,29 @@ def _find_first_nasnames(self) -> List[str]:
             nasnames = [nasname for nasname, in db_cursor.fetchall()]
             return nasnames
 
-    def _find_next_nasnames(self, from_nasname: IPvAnyAddress) -> List[str]:
+    def _find_next_nasnames(self, from_nasname: str) -> List[str]:
         with self._db_cursor() as db_cursor:
             sql = f"""SELECT DISTINCT nasname FROM {self.nas}
                       WHERE nasname > %s ORDER BY nasname LIMIT {self._PER_PAGE}"""
-            db_cursor.execute(sql, (str(from_nasname),))
+            db_cursor.execute(sql, (from_nasname,))
             nasnames = [nasname for nasname, in db_cursor.fetchall()]
             return nasnames
 
-    def find_one(self, nasname: IPvAnyAddress) -> Nas:
+    def find_one(self, nasname: str) -> Nas:
         if not self.exists(nasname):
             return None
 
         with self._db_cursor() as db_cursor:
             sql = f"SELECT nasname, shortname, secret FROM {self.nas} WHERE nasname = %s"
-            db_cursor.execute(sql, (str(nasname),))
+            db_cursor.execute(sql, (nasname,))
             n, sh, se = db_cursor.fetchone()
             return Nas(nasname=n, shortname=sh, secret=se)
 
     def add(self, nas: Nas):
         with self._db_cursor() as db_cursor:
             sql = f"INSERT INTO {self.nas} (nasname, shortname, secret) VALUES (%s, %s, %s)"
-            db_cursor.execute(sql, (str(nas.nasname), nas.shortname, nas.secret))
+            db_cursor.execute(sql, (nas.nasname, nas.shortname, nas.secret))
 
-    def remove(self, nasname: IPvAnyAddress):
+    def remove(self, nasname: str):
         with self._db_cursor() as db_cursor:
-            db_cursor.execute(f"DELETE FROM {self.nas} WHERE nasname = %s", (str(nasname),))
+            db_cursor.execute(f"DELETE FROM {self.nas} WHERE nasname = %s", (nasname,))
diff --git a/src/tests/test_pyfreeradius.py b/src/tests/test_pyfreeradius.py
index d043ca4..b24384f 100644
--- a/src/tests/test_pyfreeradius.py
+++ b/src/tests/test_pyfreeradius.py
@@ -115,9 +115,9 @@ def test_valid_nas():
 
     # Repository: finding
     assert nas_repo.find_one(n.nasname) == n
-    assert str(n.nasname) in nas_repo.find_all_nasnames()
-    assert str(n.nasname) in nas_repo.find_nasnames()
-    assert str(n.nasname) in nas_repo.find_nasnames(from_nasname="1.1.1.0")
+    assert n.nasname in nas_repo.find_all_nasnames()
+    assert n.nasname in nas_repo.find_nasnames()
+    assert n.nasname in nas_repo.find_nasnames(from_nasname="1.1.1.0")
 
     # Repository: removing
     nas_repo.remove(n.nasname)