diff --git a/templates/frr.conf.j2 b/templates/frr.conf.j2
index fbf0f33..cbdd33f 100644
--- a/templates/frr.conf.j2
+++ b/templates/frr.conf.j2
@@ -93,8 +93,8 @@ router bgp {{host_ASN}}
   advertise-default-gw
  exit-address-family
 !
-ip prefix-list AS{{host_ASN}}-OUT seq 5 permit {{host_loopback_IP}}/32
+{% if host_loopback_IP is defined %}ip prefix-list AS{{host_ASN}}-OUT seq 5 permit {{host_loopback_IP}}/32{% endif  %}
 !
-ipv6 prefix-list AS{{host_ASN}}-OUT seq 5 permit {{host_loopback_IP_v6}}/128
+{% if host_loopback_IP_v6 is defined %}ipv6 prefix-list AS{{host_ASN}}-OUT seq 5 permit {{host_loopback_IP_v6}}/128{% endif  %}
 line vty
 !