diff --git a/src/charm_config.py b/src/charm_config.py
index 5372ae9a..3f40bb9b 100644
--- a/src/charm_config.py
+++ b/src/charm_config.py
@@ -6,7 +6,7 @@
 import dataclasses
 import logging
 from enum import Enum
-from ipaddress import IPv4Address, ip_network
+from ipaddress import IPv4Address, IPv4Network, ip_network
 from typing import Optional
 
 import ops
@@ -70,7 +70,7 @@ class UpfConfig(BaseModel):  # pylint: disable=too-few-public-methods
     cni_type: CNIType = CNIType.bridge
     upf_mode: UpfMode = UpfMode.af_packet
     dnn: StrictStr = Field(default="internet", min_length=1)
-    gnb_subnet: IPvAnyNetwork = Field(default="192.168.252.3/24")
+    gnb_subnet: IPvAnyNetwork = Field(default=IPv4Network("192.168.252.0/24"))
     access_interface: Optional[StrictStr] = Field(default="")
     access_interface_mac_address: Optional[StrictStr] = Field(default="")
     access_ip: str = Field(default="192.168.252.3/24")