diff --git a/.github/workflows/smoke.yml b/.github/workflows/smoke.yml
index eb883c5..ad094d5 100644
--- a/.github/workflows/smoke.yml
+++ b/.github/workflows/smoke.yml
@@ -14,7 +14,7 @@ on:
 jobs:
 
   smoke:
-    name: Run 3 node smoke test
+    name: Run multi node smoke test
     runs-on: ubuntu-latest
     steps:
 
diff --git a/.github/workflows/smoke/build.sh b/.github/workflows/smoke/build.sh
index 2841b8d..6d66d67 100755
--- a/.github/workflows/smoke/build.sh
+++ b/.github/workflows/smoke/build.sh
@@ -11,14 +11,29 @@ mkdir ./build
     cp ../../../../nebula .
     cp ../../../../nebula-cert .
 
-    HOST="lighthouse1" AM_LIGHTHOUSE=true ../genconfig.sh >lighthouse1.yml
-    HOST="host2" LIGHTHOUSES="192.168.100.1 172.17.0.2:4242" ../genconfig.sh >host2.yml
-    HOST="host3" LIGHTHOUSES="192.168.100.1 172.17.0.2:4242" ../genconfig.sh >host3.yml
+    HOST="lighthouse1" \
+        AM_LIGHTHOUSE=true \
+        ../genconfig.sh >lighthouse1.yml
+
+    HOST="host2" \
+        LIGHTHOUSES="192.168.100.1 172.17.0.2:4242" \
+        ../genconfig.sh >host2.yml
+
+    HOST="host3" \
+        LIGHTHOUSES="192.168.100.1 172.17.0.2:4242" \
+        INBOUND='[{"port": "any", "proto": "icmp", "group": "lighthouse"}]' \
+        ../genconfig.sh >host3.yml
+
+    HOST="host4" \
+        LIGHTHOUSES="192.168.100.1 172.17.0.2:4242" \
+        OUTBOUND='[{"port": "any", "proto": "icmp", "group": "lighthouse"}]' \
+        ../genconfig.sh >host4.yml
 
     ./nebula-cert ca -name "Smoke Test"
-    ./nebula-cert sign -name "lighthouse1" -ip "192.168.100.1/24"
-    ./nebula-cert sign -name "host2" -ip "192.168.100.2/24"
-    ./nebula-cert sign -name "host3" -ip "192.168.100.3/24"
+    ./nebula-cert sign -name "lighthouse1" -groups "lighthouse,lighthouse1" -ip "192.168.100.1/24"
+    ./nebula-cert sign -name "host2" -groups "host,host2" -ip "192.168.100.2/24"
+    ./nebula-cert sign -name "host3" -groups "host,host3" -ip "192.168.100.3/24"
+    ./nebula-cert sign -name "host4" -groups "host,host4" -ip "192.168.100.4/24"
 )
 
 docker build -t nebula:smoke .
diff --git a/.github/workflows/smoke/genconfig.sh b/.github/workflows/smoke/genconfig.sh
index cc9a3f2..81ace79 100755
--- a/.github/workflows/smoke/genconfig.sh
+++ b/.github/workflows/smoke/genconfig.sh
@@ -2,6 +2,7 @@
 
 set -e
 
+FIREWALL_ALL='[{"port": "any", "proto": "any", "host": "any"}]'
 
 if [ "$STATIC_HOSTS" ] || [ "$LIGHTHOUSES" ]
 then
@@ -48,13 +49,6 @@ tun:
   dev: ${TUN_DEV:-nebula1}
 
 firewall:
-  outbound:
-    - port: any
-      proto: any
-      host: any
-
-  inbound:
-    - port: any
-      proto: any
-      host: any
+  outbound: ${OUTBOUND:-$FIREWALL_ALL}
+  inbound: ${INBOUND:-$FIREWALL_ALL}
 EOF
diff --git a/.github/workflows/smoke/smoke.sh b/.github/workflows/smoke/smoke.sh
index df73ea1..2e06f7d 100755
--- a/.github/workflows/smoke/smoke.sh
+++ b/.github/workflows/smoke/smoke.sh
@@ -5,6 +5,7 @@ set -e -x
 docker run --name lighthouse1 --rm nebula:smoke -config lighthouse1.yml -test
 docker run --name host2 --rm nebula:smoke -config host2.yml -test
 docker run --name host3 --rm nebula:smoke -config host3.yml -test
+docker run --name host4 --rm nebula:smoke -config host4.yml -test
 
 docker run --name lighthouse1 --device /dev/net/tun:/dev/net/tun --cap-add NET_ADMIN --rm nebula:smoke -config lighthouse1.yml &
 sleep 1
@@ -12,6 +13,8 @@ docker run --name host2 --device /dev/net/tun:/dev/net/tun --cap-add NET_ADMIN -
 sleep 1
 docker run --name host3 --device /dev/net/tun:/dev/net/tun --cap-add NET_ADMIN --rm nebula:smoke -config host3.yml &
 sleep 1
+docker run --name host4 --device /dev/net/tun:/dev/net/tun --cap-add NET_ADMIN --rm nebula:smoke -config host4.yml &
+sleep 1
 
 set +x
 echo
@@ -27,7 +30,8 @@ echo " *** Testing ping from host2"
 echo
 set -x
 docker exec host2 ping -c1 192.168.100.1
-docker exec host2 ping -c1 192.168.100.3
+# Should fail because not allowed by host3 inbound firewall
+! docker exec host2 ping -c1 192.168.100.3 -w5 || exit 1
 
 set +x
 echo
@@ -36,3 +40,24 @@ echo
 set -x
 docker exec host3 ping -c1 192.168.100.1
 docker exec host3 ping -c1 192.168.100.2
+
+set +x
+echo
+echo " *** Testing ping from host4"
+echo
+set -x
+docker exec host4 ping -c1 192.168.100.1
+# Should fail because not allowed by host4 outbound firewall
+! docker exec host4 ping -c1 192.168.100.2 -w5 || exit 1
+! docker exec host4 ping -c1 192.168.100.3 -w5 || exit 1
+
+set +x
+echo
+echo " *** Testing conntrack"
+echo
+set -x
+# host2 can ping host3 now that host3 pinged it first
+docker exec host2 ping -c1 192.168.100.3
+# host4 can ping host2 once conntrack established
+docker exec host2 ping -c1 192.168.100.4
+docker exec host4 ping -c1 192.168.100.2