diff --git a/roles/network/templates/network/dhcpcd.conf.j2 b/roles/network/templates/network/dhcpcd.conf.j2
index bc8f47ebd..b44eb297d 100644
--- a/roles/network/templates/network/dhcpcd.conf.j2
+++ b/roles/network/templates/network/dhcpcd.conf.j2
@@ -38,7 +38,9 @@ require dhcp_server_identifier
 slaac private
 
 # IIAB
+{% if iiab_wireless_lan_iface is defined %}
 denyinterfaces {{ iiab_wireless_lan_iface }}
+{% endif %}
 
 # Setting iiab_wired_lan_iface would install the device as a slave under
 # br0 so we need to turn off the dhcp client in that network layout.