diff --git a/overlay_address.h b/overlay_address.h
index f480857b..fe725f50 100644
--- a/overlay_address.h
+++ b/overlay_address.h
@@ -70,6 +70,9 @@ struct subscriber{
   
   // if reachable&REACHABLE_UNICAST send packets to this address, else use the interface broadcast address
   struct sockaddr_in address;
+  time_ms_t last_probe;
+  time_ms_t last_rx;
+  time_ms_t last_tx;
   
   // public signing key details for remote peers
   unsigned char sas_public[SAS_SIZE];
diff --git a/overlay_mdp_services.c b/overlay_mdp_services.c
index 9723aa91..be899e93 100644
--- a/overlay_mdp_services.c
+++ b/overlay_mdp_services.c
@@ -305,7 +305,7 @@ overlay_mdp_service_probe(overlay_mdp_frame *mdp)
   if (probe->addr.sin_family!=AF_INET)
     RETURN(WHY("Unsupported address family"));
   
-  if (peer->reachable == REACHABLE_NONE || peer->reachable == REACHABLE_INDIRECT){
+  if (peer->reachable == REACHABLE_NONE || peer->reachable == REACHABLE_INDIRECT || (peer->reachable & REACHABLE_ASSUMED)){
     reachable_unicast(peer, &overlay_interfaces[probe->interface], probe->addr.sin_addr, probe->addr.sin_port);
   }
   RETURN(0);
@@ -318,6 +318,11 @@ int overlay_send_probe(struct subscriber *peer, struct sockaddr_in addr, overlay
   if (!interface)
     return WHY("I don't know which interface to use");
   
+  time_ms_t now = gettime_ms();
+  
+  if (peer && peer->last_probe+1000>now)
+    return -1;
+    
   struct overlay_frame *frame=malloc(sizeof(struct overlay_frame));
   bzero(frame,sizeof(struct overlay_frame));
   frame->type=OF_TYPE_DATA;
@@ -335,6 +340,9 @@ int overlay_send_probe(struct subscriber *peer, struct sockaddr_in addr, overlay
   if ((!peer) || !(peer->reachable&REACHABLE))
     my_subscriber->send_full=1;
   
+  if (peer)
+    peer->last_probe=gettime_ms();
+  
   if (overlay_mdp_encode_ports(frame->payload, MDP_PORT_ECHO, MDP_PORT_PROBE)){
     op_free(frame);
     return -1;
diff --git a/overlay_packetformats.c b/overlay_packetformats.c
index c5f8c535..9c5310f3 100644
--- a/overlay_packetformats.c
+++ b/overlay_packetformats.c
@@ -214,6 +214,7 @@ int packetOkOverlay(struct overlay_interface *interface,unsigned char *packet, s
     
     // always update the IP address we heard them from, even if we don't need to use it right now
     context.sender->address = f.recvaddr;
+    context.sender->last_rx = now;
     
     // if this is a dummy announcement for a node that isn't in our routing table
     if (context.sender->reachable == REACHABLE_NONE && 
@@ -221,7 +222,8 @@ int packetOkOverlay(struct overlay_interface *interface,unsigned char *packet, s
 	packet_flags&PACKET_UNICAST){
       
       // mark this subscriber as reachable directly via unicast.
-      reachable_unicast(context.sender, interface, f.recvaddr.sin_addr, ntohs(f.recvaddr.sin_port));
+      context.sender->interface = interface;
+      set_reachable(context.sender, REACHABLE_UNICAST|REACHABLE_ASSUMED);
     }
   }
   
@@ -306,6 +308,9 @@ int packetOkOverlay(struct overlay_interface *interface,unsigned char *packet, s
     
     int next_payload = b->position + payload_len;
     
+    if (f.source)
+      f.source->last_rx = now;
+    
     // if we can't understand one of the addresses, skip processing the payload
     if (context.invalid_addresses)
       goto next;
diff --git a/overlay_queue.c b/overlay_queue.c
index b08254bc..e91dc702 100644
--- a/overlay_queue.c
+++ b/overlay_queue.c
@@ -420,6 +420,11 @@ overlay_stuff_packet(struct outgoing_packet *packet, overlay_txqueue *queue, tim
       goto skip;
     }
     
+    if (frame->destination)
+      frame->destination->last_tx=now;
+    if (frame->next_hop)
+      frame->next_hop->last_tx=now;
+    
     // don't send rhizome adverts if the packet contains a voice payload
     if (frame->queue==OQ_ISOCHRONOUS_VOICE)
       packet->add_advertisements=0;