diff --git a/src/ca/tcpiiu.cpp b/src/ca/tcpiiu.cpp
index 2cab0c40a..80d8d48ea 100644
--- a/src/ca/tcpiiu.cpp
+++ b/src/ca/tcpiiu.cpp
@@ -88,7 +88,7 @@ void tcpiiu::connect ()
      * attempt to connect to a CA server
      */
     this->armSendWatchdog ();
-    while (1) {
+    while ( ! this->sockCloseCompleted ) {
         int errnoCpy;
 
         osiSockAddr addr = this->ipToA.address ();
@@ -211,6 +211,10 @@ unsigned tcpiiu::sendBytes ( const void *pBuf, unsigned nBytesInBuf )
     int status;
     unsigned nBytes;
 
+    if ( this->state != iiu_connected ) {
+        return 0u;
+    }
+
     assert ( nBytesInBuf <= INT_MAX );
     this->clientCtx ().enableCallbackPreemption ();
     this->armSendWatchdog ();
@@ -388,7 +392,8 @@ tcpiiu::tcpiiu ( cac &cac, const osiSockAddr &addrIn,
     recvMessagePending ( false ),
     flushPending ( false ),
     msgHeaderAvailable ( false ),
-    claimsPending ( false )
+    claimsPending ( false ),
+    sockCloseCompleted ( false )
 {
     SOCKET newSocket;
     int status;
@@ -532,6 +537,9 @@ tcpiiu::tcpiiu ( cac &cac, const osiSockAddr &addrIn,
  */
 void tcpiiu::cleanShutdown ()
 {
+    this->cancelSendWatchdog ();
+    this->cancelRecvWatchdog ();
+
     this->lock ();
     if ( this->state != iiu_disconnected ) {
         this->state = iiu_disconnected;
@@ -545,7 +553,7 @@ void tcpiiu::cleanShutdown ()
                     SOCKERRSTR (SOCKERRNO) );
             }
             else {
-                this->sock = INVALID_SOCKET;
+                this->sockCloseCompleted = true;
             }
         }
         semBinaryGive ( this->sendThreadFlushSignal );
@@ -560,15 +568,18 @@ void tcpiiu::cleanShutdown ()
  */
 void tcpiiu::forcedShutdown ()
 {
+    this->cancelSendWatchdog ();
+    this->cancelRecvWatchdog ();
+
     this->lock ();
     if ( this->state != iiu_disconnected ) {
         this->state = iiu_disconnected;
  
+        // force abortive shutdown sequence (discard outstanding sends
+        // and receives
         struct linger tmpLinger;
         tmpLinger.l_onoff = true;
         tmpLinger.l_linger = 0u;
-
-        // force abortive clousure
         int status = setsockopt ( this->sock, SOL_SOCKET, SO_LINGER, 
             reinterpret_cast <char *> ( &tmpLinger ), sizeof (tmpLinger) );
         if ( status != 0 ) {
@@ -582,7 +593,7 @@ void tcpiiu::forcedShutdown ()
                 SOCKERRSTR (SOCKERRNO) );
         }
         else {
-            this->sock = INVALID_SOCKET;
+            this->sockCloseCompleted = true;
         }
 
         semBinaryGive ( this->sendThreadFlushSignal );
@@ -616,9 +627,51 @@ tcpiiu::~tcpiiu ()
 
     this->cleanShutdown ();
 
-    // wait for send and recv threads to exit
-    semBinaryMustTake ( this->sendThreadExitSignal );
-    semBinaryMustTake ( this->recvThreadExitSignal );
+    // wait for send thread to exit
+    static const double shutdownDelay = 15.0;
+    semTakeStatus semStat;
+    while ( true ) {
+        semStat = semBinaryTakeTimeout ( this->sendThreadExitSignal, shutdownDelay );
+        if ( semStat == semTakeOK ) {
+            break;
+        }
+        assert ( semStat == semTakeTimeout );
+        if ( ! this->sockCloseCompleted ) {
+            printf ( "Gave up waiting for \"shutdown()\" to force send thread to exit after %f sec\n", 
+                shutdownDelay);
+            printf ( "Closing socket\n" );
+            int status = socket_close ( this->sock );
+            if ( status ) {
+                errlogPrintf ("CAC TCP socket close error was %s\n", 
+                    SOCKERRSTR ( SOCKERRNO ) );
+            }
+            else {
+                this->sockCloseCompleted = true;
+            }
+        }
+    }
+
+    // wait for recv thread to exit
+    while ( true ) {
+        semStat = semBinaryTakeTimeout ( this->recvThreadExitSignal, shutdownDelay );
+        if ( semStat == semTakeOK ) {
+            break;
+        }
+        assert ( semStat == semTakeTimeout );
+        if ( ! this->sockCloseCompleted ) {
+            printf ( "Gave up waiting for \"shutdown()\" to force receive thread to exit after %f sec\n", 
+                shutdownDelay);
+            printf ( "Closing socket\n" );
+            int status = socket_close ( this->sock );
+            if ( status ) {
+                errlogPrintf ("CAC TCP socket close error was %s\n", 
+                    SOCKERRSTR ( SOCKERRNO ) );
+            }
+            else {
+                this->sockCloseCompleted = true;
+            }
+        }
+    }
 
     semBinaryDestroy ( this->sendThreadExitSignal );
     semBinaryDestroy ( this->recvThreadExitSignal );
@@ -632,7 +685,7 @@ tcpiiu::~tcpiiu ()
         free ( this->pCurData );
     }
 
-    if ( this->sock != INVALID_SOCKET ) {
+    if ( ! this->sockCloseCompleted ) {
         int status = socket_close ( this->sock );
         if ( status ) {
             errlogPrintf ("CAC TCP socket close error was %s\n",