diff --git a/test/120_discovery_test.sh b/test/120_discovery_test.sh
new file mode 100755
index 00000000..447b3721
--- /dev/null
+++ b/test/120_discovery_test.sh
@@ -0,0 +1,41 @@
+#! /bin/bash
+
+. ./config.sh
+
+C1=10.2.1.41
+C3=10.2.1.71
+
+launch_all() {
+    weave_on $HOST1 launch-router $1
+    weave_on $HOST2 launch-router $1 --ipalloc-range="" $HOST1
+    weave_on $HOST3 launch-router $1                    $HOST2
+}
+
+start_suite "Peer discovery, multi-hop routing and gossip forwarding"
+
+launch_all
+
+start_container $HOST1 $C1/24 --name=c1
+start_container $HOST3 $C3/24 --name=c3
+
+assert_raises "exec_on $HOST1 c1 $PING $C3"
+stop_router_on $HOST2
+assert_raises "exec_on $HOST1 c1 $PING $C3"
+
+stop_router_on $HOST1
+stop_router_on $HOST3
+
+launch_all --no-discovery
+
+sleep 5 # give topology gossip some time to propagate
+
+assert_raises "exec_on $HOST1 c1 $PING $C3"
+
+# this stalls if gossip forwarding doesn't work. We wait for slightly
+# longer than the gossip interval (30s) before giving up.
+assert_raises "timeout 40 cat <( start_container $HOST3 )"
+
+stop_router_on $HOST2
+assert_raises "exec_on $HOST1 c1 sh -c '! $PING $C3'"
+
+end_suite
diff --git a/test/Vagrantfile b/test/Vagrantfile
index 73be67e3..1a888f40 100644
--- a/test/Vagrantfile
+++ b/test/Vagrantfile
@@ -5,7 +5,7 @@ VAGRANTFILE_API_VERSION = "2"
 Vagrant.require_version ">= 1.7.0"
 
 # these ought to match what is in config.sh
-n_machines = 2
+n_machines = 3
 ip_prefix = "192.168.48"
 ip_suffix_base = 10
 
diff --git a/test/config.sh b/test/config.sh
index 31159e4a..3d136999 100644
--- a/test/config.sh
+++ b/test/config.sh
@@ -12,7 +12,7 @@ fi
 SOURCED_CONFIG_SH=true
 
 # these ought to match what is in Vagrantfile
-N_MACHINES=${N_MACHINES:-2}
+N_MACHINES=${N_MACHINES:-3}
 IP_PREFIX=${IP_PREFIX:-192.168.48}
 IP_SUFFIX_BASE=${IP_SUFFIX_BASE:-10}
 
@@ -26,6 +26,7 @@ fi
 # these are used by the tests
 HOST1=$(echo $HOSTS | cut -f 1 -d ' ')
 HOST2=$(echo $HOSTS | cut -f 2 -d ' ')
+HOST3=$(echo $HOSTS | cut -f 3 -d ' ')
 
 . "$DIR/assert.sh"
 
diff --git a/test/gce.sh b/test/gce.sh
index 02738928..192af733 100755
--- a/test/gce.sh
+++ b/test/gce.sh
@@ -13,7 +13,7 @@ PROJECT=${PROJECT:-positive-cocoa-90213}
 IMAGE=ubuntu-14-04
 TEMPLATE_NAME="test-template-2"
 ZONE=us-central1-a
-NUM_HOSTS=2
+NUM_HOSTS=3
 SUFFIX=""
 if [ -n "$CIRCLECI" ]; then
 	SUFFIX="-${CIRCLE_BUILD_NUM}-$CIRCLE_NODE_INDEX"