diff --git a/servershr/Client.h b/servershr/Client.h
index bc7aca0490..59604aff90 100644
--- a/servershr/Client.h
+++ b/servershr/Client.h
@@ -86,8 +86,8 @@ static inline int Client_free(Client *client, fd_set *fdactive)
     MDSDBG(CLIENT_PRI, CLIENT_VAR(client));
     if (client->reply_sock != INVALID_SOCKET)
     {
-      shutdown(client->reply_sock, 2);
-      close(client->reply_sock);
+      shutdown(client->reply_sock, SHUT_RDWR);
+      closesocket(client->reply_sock);
       if (fdactive)
         FD_CLR(client->reply_sock, fdactive);
     }
@@ -161,7 +161,7 @@ static void Client_do_message(Client *c, fd_set *fdactive)
     if (nbytes != 0)
       MDSWRN(CLIENT_PRI " Invalid read %d/60", CLIENT_VAR(c), nbytes);
     else
-      MDSDBG(CLIENT_PRI " Clint disconnected", CLIENT_VAR(c));
+      MDSDBG(CLIENT_PRI " Client disconnected", CLIENT_VAR(c));
     Client_remove(c, fdactive);
     return;
   }
diff --git a/servershr/ServerDispatchPhase.c b/servershr/ServerDispatchPhase.c
index 486d87e6e4..6e4ece624c 100644
--- a/servershr/ServerDispatchPhase.c
+++ b/servershr/ServerDispatchPhase.c
@@ -634,20 +634,16 @@ static void dispatch(int i)
     }
     else
     {
+      actions[i].dispatched = 1;
       UNLOCK_ACTION(i, d_w);
       status = ServerDispatchAction(
           0, Server(server, actions[i].server), table->tree, table->shot,
           actions[i].nid, action_done, (void *)(intptr_t)i, &actions[i].status,
           &actions[i].lock, &actions[i].netid, before);
-      if (STATUS_OK)
-      {
-        WRLOCK_ACTION(i, d_w);
-        actions[i].dispatched = 1;
-        UNLOCK_ACTION(i, d);
-      }
-      else
+      if (STATUS_NOT_OK)
       {
         WRLOCK_ACTION(i, d_w);
+        actions[i].dispatched = 0;
         actions[i].status = status;
         action_done_action_locked(i);
         UNLOCK_ACTION(i, d);
diff --git a/servershr/ServerQAction.c b/servershr/ServerQAction.c
index 3351fc26e1..80b3387122 100644
--- a/servershr/ServerQAction.c
+++ b/servershr/ServerQAction.c
@@ -75,9 +75,9 @@ static int DoSrvClose(SrvJob *job_in);
 static int DoSrvCreatePulse(SrvJob *job_in);
 static void DoSrvMonitor(SrvJob *job_in);
 
-static void RemoveClient(SrvJob *job);
 extern uint32_t MdsGetClientAddr();
 extern char *GetPortname();
+static pthread_mutex_t ClientsMutex = PTHREAD_MUTEX_INITIALIZER;
 static ClientList *Clients = NULL;
 
 static MonitorList *Monitors = NULL;
@@ -838,65 +838,135 @@ static void KillWorker()
 }
 
 // both
-static SOCKET AttachPort(uint32_t addr, uint16_t port)
+static void close_socket(SOCKET sock)
+{
+  shutdown(sock, SHUT_RDWR);
+  closesocket(sock);
+}
+static SOCKET open_socket(uint32_t addr, uint16_t port)
 {
-  SOCKET sock;
   struct sockaddr_in sin;
-  ClientList *l, *new;
-  for (l = Clients; l; l = l->next)
-    if (l->addr == addr && l->port == port)
-      return l->sock;
   sin.sin_port = htons(port);
   sin.sin_family = AF_INET;
   *(uint32_t *)(&sin.sin_addr) = addr;
-  sock = socket(AF_INET, SOCK_STREAM, 0);
-  if (sock == INVALID_SOCKET)
+  SOCKET sock = socket(AF_INET, SOCK_STREAM, 0);
+  if (sock != INVALID_SOCKET)
   {
-    MDSERR("Cannot get socket for " IPADDRPRI ":%u", IPADDRVAR(&addr), port);
+    if (connect(sock, (struct sockaddr *)&sin, sizeof(sin)) == 0)
+    {
+      MDSDBG("Connected to " IPADDRPRI ":%u", IPADDRVAR(&addr), port);
+      return sock;
+    }
+    MDSERR("Cannot connect to " IPADDRPRI ":%u", IPADDRVAR(&addr), port);
+    close_socket(sock);
   }
   else
   {
-    if (connect(sock, (struct sockaddr *)&sin, sizeof(sin)) == -1)
+    MDSERR("Cannot get socket for " IPADDRPRI ":%u", IPADDRVAR(&addr), port);
+  }
+  return INVALID_SOCKET;
+}
+static void add_client(uint32_t addr, uint16_t port, SOCKET sock)
+{
+  ClientList *new = (ClientList *)malloc(sizeof(ClientList));
+  new->addr = addr;
+  new->port = port;
+  new->sock = sock;
+  MDSDBG("add socket %" PRI_SOCKET " for " IPADDRPRI ":%u", new->sock, IPADDRVAR(&new->addr), new->port);
+  pthread_mutex_lock(&ClientsMutex);
+  new->next = Clients;
+  Clients = new;
+  pthread_mutex_unlock(&ClientsMutex);
+}
+static int check_socket(SOCKET socket)
+{
+  if (socket != INVALID_SOCKET)
+  {
+    fd_set fdactive;
+    FD_ZERO(&fdactive);
+    FD_SET(socket, &fdactive);
+    struct timeval timeout = {0, 0}; // non-blocking
+    return select(socket + 1, &fdactive, 0, 0, &timeout) == 0;
+  }
+  return B_FALSE;
+}
+static SOCKET find_client(uint32_t addr, uint16_t port)
+{
+  ClientList **p;
+  SOCKET sock = INVALID_SOCKET;
+  pthread_mutex_lock(&ClientsMutex);
+  for (p = &Clients; *p != NULL; p = &(*p)->next)
+  {
+    if ((*p)->addr == addr && (*p)->port == port)
     {
-      MDSERR("Cannot connect to " IPADDRPRI ":%u", IPADDRVAR(&addr), port);
-      shutdown(sock, 2);
-      close(sock);
-      return INVALID_SOCKET;
+      ClientList *l = *p;
+      if (check_socket(l->sock))
+      {
+        sock = l->sock;
+        MDSDBG("reuse socket %" PRI_SOCKET " for " IPADDRPRI ":%u", sock, IPADDRVAR(&addr), port);
+      }
+      else
+      {
+        *p = l->next;
+        close_socket(l->sock);
+        MDSDBG("cannot reuse socket %" PRI_SOCKET " for " IPADDRPRI ":%u?", l->sock, IPADDRVAR(&addr), port);
+        free(l);
+      }
+      break;
     }
-    MDSDBG("Connected to " IPADDRPRI ":%u", IPADDRVAR(&addr), port);
-    new = (ClientList *)malloc(sizeof(ClientList));
-    l = Clients;
-    Clients = new;
-    new->addr = addr;
-    new->port = port;
-    new->sock = sock;
-    new->next = l;
   }
+  pthread_mutex_unlock(&ClientsMutex);
   return sock;
 }
-// both
-static void RemoveClient(SrvJob *job)
+static SOCKET remove_client(uint32_t addr, uint16_t port)
 {
-  ClientList *l, *prev;
-  for (prev = 0, l = Clients; l;)
+  ClientList **p;
+  SOCKET sock = INVALID_SOCKET;
+  pthread_mutex_lock(&ClientsMutex);
+  for (p = &Clients; *p != NULL; p = &(*p)->next)
   {
-    if (job->h.addr == l->addr && job->h.port == l->port)
+    if ((*p)->addr == addr && (*p)->port == port)
     {
-      shutdown(l->sock, 2);
-      close(l->sock);
-      if (prev)
-        prev->next = l->next;
-      else
-        Clients = l->next;
+      ClientList *l = *p;
+      sock = l->sock;
+      *p = l->next;
       free(l);
       break;
     }
-    else
+  }
+  pthread_mutex_unlock(&ClientsMutex);
+  return sock;
+}
+static SOCKET setup_client(SrvJob *job)
+{
+  const uint32_t addr = job->h.addr;
+  const uint16_t port = job->h.port;
+  SOCKET sock = find_client(addr, port);
+  if (sock == INVALID_SOCKET)
+  {
+    sock = open_socket(addr, port);
+    if (sock != INVALID_SOCKET)
     {
-      prev = l;
-      l = l->next;
+      add_client(addr, port, sock);
+      MDSMSG("setup connection %" PRI_SOCKET " " SVRJOB_PRI, sock, SVRJOB_VAR(job));
     }
   }
+  return sock;
+}
+// both
+static void cleanup_client(SrvJob *job)
+{
+  SOCKET sock = remove_client(job->h.addr, job->h.port);
+  if (sock != INVALID_SOCKET)
+    close_socket(sock);
+  if (STATIC_Debug)
+  {
+    MDSMSG("cleanup connection %" PRI_SOCKET " " SVRJOB_PRI, sock, SVRJOB_VAR(job));
+  }
+  else
+  {
+    MDSDBG("cleanup connection %" PRI_SOCKET " " SVRJOB_PRI, sock, SVRJOB_VAR(job));
+  }
 }
 
 /// returns the number of bytes sent
@@ -910,7 +980,8 @@ static int send_all(SOCKET sock, char *msg, int len)
     const int bytes = send(sock, msg + sent, len - sent, MSG_NOSIGNAL);
     if (bytes <= 0)
     {
-      sent = bytes;
+      if (bytes != 0)
+        sent = bytes;
       break;
     }
     sent += bytes;
@@ -922,9 +993,7 @@ static int send_all(SOCKET sock, char *msg, int len)
 static int send_reply(SrvJob *job, int replyType, int status_in, int length, char *msg)
 {
   MDSDBG(SVRJOB_PRI " %d", SVRJOB_VAR(job), replyType);
-  int status;
-  status = MDSplusERROR;
-  SOCKET sock;
+  int status = MDSplusERROR;
   long msg_len = msg ? (long)strlen(msg) : 0;
   int try_again = FALSE;
   char reply[60];
@@ -933,32 +1002,30 @@ static int send_reply(SrvJob *job, int replyType, int status_in, int length, cha
   do
   {
     errno = 0;
-    sock = AttachPort(job->h.addr, (uint16_t)job->h.port);
+    SOCKET sock = setup_client(job);
     if (sock == INVALID_SOCKET)
+    {
+      MDSMSG(SVRJOB_PRI " break connection", SVRJOB_VAR(job));
       break;
+    }
     int bytes = send_all(sock, reply, 60);
+    MDSDBG("send 60: %d %d", bytes, replyType);
     if (bytes == 60)
     {
-      bytes = send_all(sock, msg, length);
-      if (bytes == length)
+      if (check_socket(sock))
       {
-        status = MDSplusSUCCESS;
-        break;
+        bytes = send_all(sock, msg, length);
+        MDSDBG("send msg: %d/%d", bytes, length);
+        if (bytes == length)
+        {
+          status = MDSplusSUCCESS;
+          break;
+        }
       }
     }
-    if (STATUS_NOT_OK)
-    {
+    else
       try_again = errno == EPIPE;
-      int debug;
-      pthread_mutex_lock(&STATIC_lock);
-      debug = STATIC_Debug;
-      pthread_mutex_unlock(&STATIC_lock);
-      if (debug)
-      {
-        MDSMSG(SVRJOB_PRI " drop connection", SVRJOB_VAR(job));
-      }
-      RemoveClient(job);
-    }
+    cleanup_client(job);
   } while (try_again--);
   return status;
 }
diff --git a/servershr/ServerSendMessage.c b/servershr/ServerSendMessage.c
index 3b3714a848..c89d339a3a 100644
--- a/servershr/ServerSendMessage.c
+++ b/servershr/ServerSendMessage.c
@@ -62,6 +62,7 @@ int ServerSendMessage();
 #include <unistd.h>
 #endif
 
+// #define DEBUG
 #include <socket_port.h>
 #include <condition.h>
 #include <ipdesc.h>
@@ -73,7 +74,6 @@ int ServerSendMessage();
 #define _NO_SERVER_SEND_MESSAGE_PROTO
 #include "servershrp.h"
 
-//#define DEBUG
 #include "Client.h"
 
 extern short ArgLen();
@@ -148,7 +148,7 @@ int ServerSendMessage(int *msgid, char *server, int op, int *retstatus,
     addr = *(uint32_t *)&addr_struct.sin_addr;
   if (!addr)
   {
-    MDSWRN("could not resolve address the socket is bound to");
+    MDSWRN("could not resolve address socket %" PRI_SOCKET " is bound to", sock);
     if (callback_done)
       callback_done(callback_param);
     return ServerSOCKET_ADDR_ERROR;
@@ -196,7 +196,7 @@ int ServerSendMessage(int *msgid, char *server, int op, int *retstatus,
   status = SendArg(conid, 0, DTYPE_CSTRING, 1, (short)(ccmd - cmd), 0, 0, cmd);
   if (STATUS_NOT_OK)
   {
-    MDSWRN("could not sending message to server");
+    MDSWRN("could not send message to server");
     Job_cleanup(status, jobid);
     return status;
   }
@@ -246,7 +246,7 @@ static SOCKET new_reply_socket(uint16_t *port_out)
     {
       char *dash;
       for (dash = range; *dash && *dash != '-'; dash++)
-        ;
+        continue;
       if (dash)
         *(dash++) = 0;
       start_port = (uint16_t)(strtol(range, NULL, 0) & 0xffff);
@@ -527,16 +527,32 @@ static inline int server_connect(char *server, uint32_t addr, uint16_t port)
 {
   int conid;
   LOCK_CLIENTS;
-  conid = ConnectToMds(server);
-  if (conid != INVALID_CONNECTION_ID)
+  Client *c = Client_get_by_addr_and_port_locked(addr, port);
+  if (c && get_socket_by_conid(c->conid) != INVALID_SOCKET)
   {
-    Client *c = newClient(addr, port, conid);
-    MDSDBG(CLIENT_PRI " connected to %s", CLIENT_VAR(c), server);
-    Client_push_locked(c);
+    conid = c->conid;
   }
   else
   {
-    MDSWRN("Could not connect to %s (" IPADDRPRI ":%d)", server, IPADDRVAR(&addr), port);
+    conid = ConnectToMds(server);
+    if (conid != INVALID_CONNECTION_ID)
+    {
+      if (c)
+      {
+        MDSDBG(CLIENT_PRI " re-connected to %s as %d", CLIENT_VAR(c), server, conid);
+        c->conid = conid;
+      }
+      else
+      {
+        c = newClient(addr, port, conid);
+        MDSDBG(CLIENT_PRI " connected to %s", CLIENT_VAR(c), server);
+        Client_push_locked(c);
+      }
+    }
+    else
+    {
+      MDSWRN("Could not connect to %s (" IPADDRPRI ":%d)", server, IPADDRVAR(&addr), port);
+    }
   }
   UNLOCK_CLIENTS;
   return conid;
@@ -585,7 +601,7 @@ static void accept_client(SOCKET reply_sock, struct sockaddr_in *sin, fd_set *fd
   else
   {
     MDSWRN("Dropped connection from " IPADDRPRI ":%d", IPADDRVAR(&addr), port);
-    shutdown(reply_sock, 2);
-    close(reply_sock);
+    shutdown(reply_sock, SHUT_RDWR);
+    closesocket(reply_sock);
   }
 }
diff --git a/servershr/servershrp.h b/servershr/servershrp.h
index c1ff748c7b..8d6b84bbe1 100644
--- a/servershr/servershrp.h
+++ b/servershr/servershrp.h
@@ -4,11 +4,13 @@
 #include <mdsdescrip.h>
 #ifdef _WIN32
 #include <time.h>
+#define PRI_SOCKET PRIdPTR
 #else
 #ifndef HAVE_PTHREAD_LOCK_GLOBAL_NP
 extern void pthread_lock_global_np();
 extern void pthread_unlock_global_np();
 #endif
+#define PRI_SOCKET "d"
 #endif
 
 #ifdef MDSOBJECTSCPPSHRVS_EXPORTS