diff --git a/docs/caveats.md b/docs/caveats.md
index 7536ddcd36..0781ff5913 100644
--- a/docs/caveats.md
+++ b/docs/caveats.md
@@ -169,7 +169,8 @@ and validation. Configuration is deployed with a bash script executed within the
 * We did not implement OSPFv3 for ASAv
 * ASAv static routes require an outgoing interface. *netlab* does not configure static routes with indirect next hops on ASAv.
 * ASAv does not support equal-cost static routes over multiple interfaces. *netlab* configures only the first next hop of a static route.
-* ASAv releases before 9.18(2) do not support loopback interfaces. As *netlab* uses loopback interfaces for iBGP sessions, iBGP sessions with ASAv nodes are not configured. Use eBGP sessions instead.
+* ASAv releases before 9.18(2) do not support loopback interfaces; *netlab* does not configure them by default. Set `loopback: true` on ASAv nodes running release 9.18(2) or later.
+* *netlab* uses loopback interfaces for IBGP sessions. IBGP sessions with ASAv nodes that have no loopback interface do not work; use EBGP sessions instead.
 * OSPF routes are not imported into the IPv6 BGP address family (OSPFv3 is not implemented). Routing policies cannot be used with route import.
 
 (caveats-cat8000v)=
diff --git a/netsim/ansible/templates/bgp/asa.j2 b/netsim/ansible/templates/bgp/asa.j2
index 635d28e029..ff50f3afa3 100644
--- a/netsim/ansible/templates/bgp/asa.j2
+++ b/netsim/ansible/templates/bgp/asa.j2
@@ -9,8 +9,7 @@ router bgp {{ bgp.as }}
 {% for af in ['ipv4','ipv6'] if bgp[af] is defined %}
   address-family {{ af }} unicast
 {%   for n in bgp.neighbors if n[af] is defined %}
-    neighbor {{ n[af] }} remote-as {{ n.as }}
-    neighbor {{ n[af] }} description {{ n.name }}
+{{ bgpcfg.neighbor_global(n,n[af]) }}
 {%   endfor %}
 {%   if bgp.import is defined %}
 {{     redistribute.config(bgp,af=af,ospf_pid=ospf.process|default(1))|indent(2,first=True) }}
diff --git a/netsim/ansible/templates/bgp/asa.macro.j2 b/netsim/ansible/templates/bgp/asa.macro.j2
index 5b4065d6f6..aa3f7d1409 100644
--- a/netsim/ansible/templates/bgp/asa.macro.j2
+++ b/netsim/ansible/templates/bgp/asa.macro.j2
@@ -1,3 +1,13 @@
+{#
+   BGP neighbor definition: remote-as, description, update-source
+#}
+{% macro neighbor_global(n,ip) %}
+    neighbor {{ ip }} remote-as {{ n.as }}
+    neighbor {{ ip }} description {{ n.name }}
+{% if n._source_intf is defined %}
+    neighbor {{ ip }} update-source {{ n._source_intf.ifname }}
+{% endif %}
+{%- endmacro -%}
 {#
    Address family BGP neighbor definition
 #}
diff --git a/netsim/ansible/templates/initial/asa.j2 b/netsim/ansible/templates/initial/asa.j2
index 35edda3197..29beb07c6c 100644
--- a/netsim/ansible/templates/initial/asa.j2
+++ b/netsim/ansible/templates/initial/asa.j2
@@ -9,6 +9,17 @@ name {{ v.loopback.ipv4|ansible.utils.ipaddr('address') }} {{ k }}
 {%   endfor %}
 {% endif %}
 !
+{% if loopback is defined %}
+interface {{ loopback.ifname }}
+ nameif {{ loopback.ifname }}
+{%   if 'ipv4' in loopback %}
+ ip address {{ loopback.ipv4|ansible.utils.ipaddr('address') }} {{ loopback.ipv4|ansible.utils.ipaddr('netmask') }}
+{%   endif %}
+{%   if 'ipv6' in loopback %}
+ ipv6 address {{ loopback.ipv6|upper }}
+{%   endif %}
+{% endif %}
+!
 {% for l in interfaces|default([]) %}
 interface {{ l.ifname }}
 {%   if l.shutdown|default(False) %}
diff --git a/netsim/devices/asav.py b/netsim/devices/asav.py
index 897c4e366a..c4674808e3 100644
--- a/netsim/devices/asav.py
+++ b/netsim/devices/asav.py
@@ -21,6 +21,19 @@ def check_isis_p2p_interfaces(node: Box, topology: Box, igp: str = 'isis') -> No
       more_data=[ f'Node {node.name} {intf.ifname} ({intf.name})' ],
       category=log.IncorrectType)
 
+def check_ibgp_loopback(node: Box) -> None:
+  if 'loopback' in node:
+    return
+  if not any(n.type == 'ibgp' for n in node.get('bgp.neighbors',[])):
+    return
+
+  report_quirk(
+    text=f"ASAv node '{node.name}' has no loopback, iBGP sessions will not work",
+    node=node,
+    quirk='ibgp_no_loopback',
+    more_hints=[ 'Set loopback: true on ASAv 9.18(2) or later, or use eBGP' ],
+    category=Warning)
+
 class ASA(_Quirks):
 
   @classmethod
@@ -36,3 +49,6 @@ def device_quirks(self, node: Box, topology: Box) -> None:
         text=f"netlab cannot configure OSPFv3 on ASAv node '{node.name}'",
         node=node,
         category=log.IncorrectType)
+
+    if 'bgp' in mods:
+      check_ibgp_loopback(node)
diff --git a/netsim/devices/asav.yml b/netsim/devices/asav.yml
index 8db41902cc..30dad548e4 100644
--- a/netsim/devices/asav.yml
+++ b/netsim/devices/asav.yml
@@ -2,6 +2,8 @@
 description: Cisco ASAv
 support:
   level: minimal
+loopback_interface_name: Loopback{ifindex}
+loopback: false
 interface_name: GigabitEthernet0/{ifindex}
 ifindex_offset: 0
 mgmt_if: Management0/0