diff --git a/pycroft/model/net.py b/pycroft/model/net.py
index 710f149f3..f644bcfe5 100644
--- a/pycroft/model/net.py
+++ b/pycroft/model/net.py
@@ -56,18 +56,27 @@ class Subnet(IntegerIdModel):
     # /backrefs
 
     @property
-    def usable_ip_range(self) -> netaddr.IPRange | None:
-        """All IPs in this subnet which are not reserved."""
+    def reserved_ipset(self) -> netaddr.IPSet:
+        res_bottom = self.reserved_addresses_bottom or 0
+        res_top = self.reserved_addresses_top or 0
         # takes care of host- and broadcast domains plus edge-cases (e.g. /32)
         first_usable, last_usable = self.address._usable_range()
+        return netaddr.IPSet(
+            [
+                netaddr.IPRange(self.address[0], first_usable + res_bottom),
+                netaddr.IPRange(last_usable - res_top, self.address[-1]),
+            ]
+        )
 
-        res_bottom = self.reserved_addresses_bottom or 0
-        res_top = self.reserved_addresses_top or 0
-        first_usable = first_usable + res_bottom
-        last_usable = last_usable + res_top
-        if last_usable < first_usable:
-            return None
-        return netaddr.IPRange(first_usable, last_usable)
+    def reserved_ip_ranges_iter(self) -> t.Iterator[netaddr.IPRange]:
+        return self.reserved_ipset.iter_ipranges()
+
+    @property
+    def usable_ip_range(self) -> netaddr.IPRange | None:
+        """All IPs in this subnet which are not reserved."""
+        usable = netaddr.IPSet(self.address) - self.reserved_ipset
+        assert usable.iscontiguous(), f"Complement of reserved ranges in {self} is not contiguous"
+        return usable.iprange()
 
     @property
     def usable_size(self) -> int:
diff --git a/tests/frontend/test_infrastructure.py b/tests/frontend/test_infrastructure.py
index f50ff30ea..e5cb4d729 100644
--- a/tests/frontend/test_infrastructure.py
+++ b/tests/frontend/test_infrastructure.py
@@ -5,7 +5,7 @@
 import typing as t
 
 import pytest
-from netaddr import IPAddress, IPNetwork
+from netaddr import IPNetwork
 from sqlalchemy.orm import Session
 from flask import url_for
 
@@ -15,7 +15,6 @@
 from pycroft.model.port import PatchPort
 from tests import factories as f
 from tests.assertions import assert_one
-from web.blueprints.infrastructure import format_address_range
 from .assertions import TestClient
 
 
@@ -31,11 +30,6 @@ def client(module_test_client: TestClient) -> TestClient:
     return module_test_client
 
 
-def test_format_empty_address_range():
-    with pytest.raises(ValueError):
-        format_address_range(IPAddress("141.30.228.39"), amount=0)
-
-
 @pytest.mark.usefixtures("admin_logged_in", "session")
 class TestSubnets:
     @pytest.fixture(scope="class", autouse=True)
diff --git a/web/blueprints/host/__init__.py b/web/blueprints/host/__init__.py
index 7924a59ba..2b2ae4225 100644
--- a/web/blueprints/host/__init__.py
+++ b/web/blueprints/host/__init__.py
@@ -4,7 +4,7 @@
 from flask.typing import ResponseReturnValue
 from flask_login import current_user
 from flask_wtf import FlaskForm
-from ipaddr import IPv4Address
+from netaddr import IPAddress
 
 from pycroft.exc import PycroftException
 from pycroft.helpers.net import mac_regex, get_interface_manufacturer
@@ -269,7 +269,7 @@ def default_response() -> ResponseReturnValue:
     if not form.validate():
         return default_response()
 
-    ips = {IPv4Address(ip) for ip in form.ips.data}
+    ips = {IPAddress(ip) for ip in form.ips.data}
 
     with abort_on_error(default_response), session.session.begin_nested():
         lib_host.interface_edit(
@@ -306,7 +306,7 @@ def default_response() -> ResponseReturnValue:
     if not form.validate():
         return default_response()
 
-    ips = {IPv4Address(ip) for ip in form.ips.data}
+    ips = {IPAddress(ip) for ip in form.ips.data}
 
     try:
         lib_host.interface_create(
diff --git a/web/blueprints/infrastructure/__init__.py b/web/blueprints/infrastructure/__init__.py
index fb971e9cb..1e303a965 100644
--- a/web/blueprints/infrastructure/__init__.py
+++ b/web/blueprints/infrastructure/__init__.py
@@ -14,7 +14,7 @@
 from flask.typing import ResponseValue
 from flask_login import current_user
 from flask_wtf import FlaskForm as Form
-from ipaddr import IPAddress, _BaseIP
+from netaddr import IPAddress
 from sqlalchemy.orm import joinedload
 
 from pycroft.lib.infrastructure import create_switch, \
@@ -56,27 +56,8 @@ def subnets() -> ResponseValue:
         subnet_table=SubnetTable(data_url=url_for(".subnets_json")))
 
 
-def format_address_range(base_address: _BaseIP, amount: int) -> str:
-    if amount == 0:
-        raise ValueError
-    if abs(amount) == 1:
-        return str(base_address)
-    if amount > 1:
-        return f'{str(base_address)} - {str(base_address + amount - 1)}'
-    return f'{str(base_address + amount + 1)} - {str(base_address)}'
-
-
 def format_reserved_addresses(subnet: Subnet) -> list[str]:
-    reserved = []
-    if subnet.reserved_addresses_bottom:
-        reserved.append(
-            format_address_range(subnet.address.network + 1,
-                                 subnet.reserved_addresses_bottom))
-    if subnet.reserved_addresses_top:
-        reserved.append(
-            format_address_range(subnet.address.broadcast - 1,
-                                 -subnet.reserved_addresses_top))
-    return reserved
+    return [str(range) for range in subnet.reserved_ip_ranges_iter()]
 
 
 @bp.route('/subnets/json')
diff --git a/web/blueprints/user/log.py b/web/blueprints/user/log.py
index 889197887..68ccac3c4 100644
--- a/web/blueprints/user/log.py
+++ b/web/blueprints/user/log.py
@@ -7,7 +7,7 @@
 import logging
 import typing as t
 
-from ipaddr import _BaseIP
+from netaddr import IPAddress
 from sqlalchemy import select, Row
 from sqlalchemy.orm import Query
 
@@ -24,7 +24,7 @@
 
 logger = logging.getLogger(__name__)
 
-def iter_hades_switch_ports(room: Room) -> t.Sequence[Row[tuple[str, _BaseIP]]]:
+def iter_hades_switch_ports(room: Room) -> t.Sequence[Row[tuple[str, IPAddress]]]:
     """Return all tuples of (nasportid, nasipaddress) for a room.
 
     :param room: The room to filter by