diff --git a/ansible/roles/ip-allocation/library/ip_allocation.py b/ansible/roles/ip-allocation/library/ip_allocation.py
index 0eb3ee944..9f30bad06 100644
--- a/ansible/roles/ip-allocation/library/ip_allocation.py
+++ b/ansible/roles/ip-allocation/library/ip_allocation.py
@@ -147,6 +147,9 @@ def update_allocation(module, allocations):
             allocation_pool = netaddr.IPSet(allocation_pool)
         else:
             allocation_pool = netaddr.IPSet([network])
+            if network.prefixlen != 32:
+                reserved_ips = [network.network, network.broadcast]
+                allocation_pool -= netaddr.IPSet(reserved_ips)
         free_ips = allocation_pool - allocated_ips
         for free_cidr in free_ips.iter_cidrs():
             ip = free_cidr[0]
diff --git a/doc/source/configuration/network.rst b/doc/source/configuration/network.rst
index 455568e07..04434cdf5 100644
--- a/doc/source/configuration/network.rst
+++ b/doc/source/configuration/network.rst
@@ -157,10 +157,12 @@ To configure a network called ``example`` with VLAN ID ``123``:
 IP Address Allocation
 =====================
 
-IP addresses are allocated automatically by Kayobe from the
-allocation pool
-defined by ``allocation_pool_start`` and ``allocation_pool_end``.  The
-allocated addresses are stored in
+IP addresses are allocated automatically by Kayobe from the allocation pool
+defined by ``allocation_pool_start`` and ``allocation_pool_end``. If these
+variables are undefined, the entire network is used, except for network and
+broadcast addresses. IP addresses are only allocated if the network ``cidr`` is
+set and DHCP is not used (see ``bootproto`` in
+:ref:`configuration-network-per-host`). The allocated addresses are stored in
 ``${KAYOBE_CONFIG_PATH}/network-allocation.yml`` using the global per-network
 attribute ``ips`` which maps Ansible inventory hostnames to allocated IPs.
 
@@ -264,6 +266,8 @@ To configure a network called ``example`` with a default route and a
      - cidr: 10.1.0.0/24
        table: exampleroutetable
 
+.. _configuration-network-per-host:
+
 Per-host Network Configuration
 ==============================
 
diff --git a/releasenotes/notes/restrict-ip-allocation-8e20022110c2283e.yaml b/releasenotes/notes/restrict-ip-allocation-8e20022110c2283e.yaml
new file mode 100644
index 000000000..6441f66f3
--- /dev/null
+++ b/releasenotes/notes/restrict-ip-allocation-8e20022110c2283e.yaml
@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Stops allocating network and broadcast addresses to hosts when an allocation pool
+    is not defined.