diff --git a/directory_service.c b/directory_service.c
index fae71877..19f532f8 100644
--- a/directory_service.c
+++ b/directory_service.c
@@ -38,6 +38,7 @@ struct item{
 };
 
 struct item *root=NULL;
+static uint8_t allow_duplicates = 1;
 
 static struct item *create_item(const char *key){
   struct item *ret=calloc(1,sizeof(struct item));
@@ -62,7 +63,7 @@ static struct item *find_item(const char *key){
   return NULL;
 }
 
-static void add_item(char *key, char *value){
+static int add_item(const char *key, const char *value){
   struct item *item = root, **last_ptr=&root;
   while(item){
     int c=strcmp(item->key, key);
@@ -70,8 +71,9 @@ static void add_item(char *key, char *value){
       c=strcmp(item->value, value);
       if (c==0){
 	item->expires = gettime_ms()+1200000;
-	return;
-      }
+	return 1;
+      }else if(!allow_duplicates)
+	return -1;
     }
     if (c<0){
       last_ptr = &item->_left;
@@ -87,38 +89,47 @@ static void add_item(char *key, char *value){
   item->value[sizeof(item->value) -1]=0;
   // expire after 20 minutes
   item->expires = gettime_ms()+1200000;
-  // used by tests
-  fprintf(stderr, "PUBLISHED \"%s\" = \"%s\"\n", key, value);
+  return 0;
 }
 
-static void add_record(int mdp_sockfd){
-  int ttl;
-  overlay_mdp_frame mdp;
+static int add_record(int mdp_sockfd){
+  struct mdp_header header;
+  uint8_t payload[MDP_MTU];
   
-  if (overlay_mdp_recv(mdp_sockfd, &mdp, MDP_PORT_DIRECTORY, &ttl))
-    return;
+  ssize_t len = mdp_recv(mdp_sockfd, &header, payload, sizeof payload);
+  if (len==-1)
+    return WHY_perror("mdp_recv");
   
-  if (mdp.packetTypeAndFlags&MDP_NOCRYPT){
-    fprintf(stderr, "Only encrypted packets will be considered for publishing\n");
-    return;
-  }
+  if (header.flags & (MDP_FLAG_NO_CRYPT|MDP_FLAG_NO_SIGN))
+    return WHY("Only encrypted packets will be considered for publishing\n");
   
   // make sure the payload is a NULL terminated string
-  mdp.out.payload[mdp.out.payload_length]=0;
+  payload[len]=0;
   
-  char *did=(char *)mdp.out.payload;
-  int i=0;
-  while(i<mdp.out.payload_length && mdp.out.payload[i] && mdp.out.payload[i]!='|')
+  const char *did=(const char *)payload;
+  unsigned i=0;
+  while(i<len && payload[i] && payload[i]!='|')
     i++;
-  mdp.out.payload[i]=0;
-  char *name = (char *)mdp.out.payload+i+1;
-  char *sid = alloca_tohex_sid_t(mdp.out.src.sid);
+  payload[i]=0;
+  const char *name = (const char *)payload+i+1;
+  const char *sid = alloca_tohex_sid_t(header.remote.sid);
   
   // TODO check that did is a valid phone number
   
   char url[256];
   snprintf(url, sizeof(url), "sid://%s/local/%s|%s|%s", sid, did, did, name);
-  add_item(did, url);
+  
+  // TODO only add whitelisted entries
+  
+  int r=add_item(did, url);
+  if (r==0){
+    // used by tests
+    fprintf(stderr, "PUBLISHED \"%s\" = \"%s\"\n", did, url);
+  }
+  uint8_t response = (r==-1 ? 0:1);
+  if (mdp_send(mdp_sockfd, &header, &response, sizeof response)==-1)
+    return WHY_perror("mdp_send");
+  return 0;
 }
 
 static void respond(char *token, struct item *item, char *key){
@@ -188,20 +199,14 @@ int main(void){
   struct pollfd fds[2];
   int mdp_sockfd;
 
-  if ((mdp_sockfd = overlay_mdp_client_socket()) < 0)
+  if ((mdp_sockfd = mdp_socket()) < 0)
     return WHY("Cannot create MDP socket");
 
   // bind for incoming directory updates
-  sid_t srcsid;
-    
-  if (overlay_mdp_getmyaddr(mdp_sockfd, 0, &srcsid)) {
-    overlay_mdp_client_close(mdp_sockfd);
-    return WHY("Could not get local address");
-  }
-  if (overlay_mdp_bind(mdp_sockfd, &srcsid, MDP_PORT_DIRECTORY)) {
-    overlay_mdp_client_close(mdp_sockfd);
-    return WHY("Could not bind to MDP socket");
-  }
+  struct mdp_sockaddr local_addr = {.sid = BIND_PRIMARY, .port = MDP_PORT_DIRECTORY};
+  
+  if (mdp_bind(mdp_sockfd, &local_addr)==-1)
+    return WHY_perror("mdp_bind");
   
   fds[0].fd = STDIN_FILENO;
   fds[0].events = POLLIN;
@@ -224,6 +229,6 @@ int main(void){
     }
   }
   
-  overlay_mdp_client_close(mdp_sockfd);
+  mdp_close(mdp_sockfd);
   return 0;
 }
diff --git a/mdp_client.c b/mdp_client.c
index b41de4a0..1bac9650 100644
--- a/mdp_client.c
+++ b/mdp_client.c
@@ -155,6 +155,28 @@ ssize_t _mdp_recv(struct __sourceloc __whence, int socket, struct mdp_header *he
   return len - sizeof(struct mdp_header);
 }
 
+int _mdp_bind(struct __sourceloc __whence, int socket, struct mdp_sockaddr *local_addr)
+{
+  struct mdp_header mdp_header;
+  bzero(&mdp_header, sizeof(mdp_header));
+
+  mdp_header.local = *local_addr;
+  mdp_header.remote.port = MDP_LISTEN;
+  mdp_header.remote.sid = SID_ANY;
+  mdp_header.flags = MDP_FLAG_BIND;
+  
+  if (_mdp_send(__whence, socket, &mdp_header, NULL, 0)==-1)
+    return -1;
+  if (_mdp_recv(__whence, socket, &mdp_header, NULL, 0)==-1)
+    return -1;
+  if (mdp_header.flags & MDP_FLAG_ERROR){
+    errno = EBADMSG;
+    return -1;
+  }
+  *local_addr = mdp_header.local;
+  return 0;
+}
+
 int _mdp_poll(struct __sourceloc UNUSED(__whence), int socket, time_ms_t timeout_ms)
 {
   // TODO make overlay_mdp_client_poll() take __whence arg
diff --git a/mdp_client.h b/mdp_client.h
index 7023192a..3e77e240 100644
--- a/mdp_client.h
+++ b/mdp_client.h
@@ -145,11 +145,14 @@ int _mdp_send(struct __sourceloc, int socket, const struct mdp_header *header, c
 ssize_t _mdp_recv(struct __sourceloc, int socket, struct mdp_header *header, uint8_t *payload, size_t max_len);
 int _mdp_poll(struct __sourceloc, int socket, time_ms_t timeout_ms);
 ssize_t mdp_poll_recv(int mdp_sock, time_ms_t deadline, struct mdp_header *rev_header, unsigned char *payload, size_t buffer_size);
+int _mdp_bind(struct __sourceloc __whence, int socket, struct mdp_sockaddr *local_addr);
+
 #define mdp_socket()      _mdp_socket(__WHENCE__)
 #define mdp_close(s)      _mdp_close(__WHENCE__, (s))
 #define mdp_send(s,h,p,l) _mdp_send(__WHENCE__, (s), (h), (p), (l))
 #define mdp_recv(s,h,p,l) _mdp_recv(__WHENCE__, (s), (h), (p), (l))
 #define mdp_poll(s,t)     _mdp_poll(__WHENCE__, (s), (t))
+#define mdp_bind(s,a)     _mdp_bind(__WHENCE__, (s), (a))
 
 /* Client-side MDP function */
 int overlay_mdp_client_socket(void);