diff --git a/filter_plugins/net_utils.py b/filter_plugins/net_utils.py
new file mode 100644
index 0000000..2fd4560
--- /dev/null
+++ b/filter_plugins/net_utils.py
@@ -0,0 +1,28 @@
+import ipaddress
+
+import dns.name
+
+
+class FilterModule:
+    def filters(self):
+        return {
+            "add_origin": add_origin,
+            "add_origin_keys": add_origin_keys,
+            "ip_filter": ip_filter,
+        }
+
+
+def ip_filter(addresses, networks):
+    if isinstance(addresses, dict):
+        return {k: ip_filter(v, networks) for k, v in addresses.items()}
+    ip_networks = [ipaddress.ip_network(n) for n in networks]
+    ip_addresses = [ipaddress.ip_address(a) for a in addresses]
+    return [str(a) for a in ip_addresses if any(a in n for n in ip_networks)]
+
+
+def add_origin(name, origin="."):
+    return dns.name.from_text(name, dns.name.from_text(origin)).to_text()
+
+
+def add_origin_keys(dct, origin="."):
+    return {add_origin(k, origin): v for k, v in dct.items()}