Index: src/rsrv/caservertask.c
===================================================================
RCS file: /cvs/G/EPICS/base-3.14.12/src/rsrv/caservertask.c,v
retrieving revision 1.1
retrieving revision 1.4
diff -u -r1.1 -r1.4
--- src/rsrv/caservertask.c	29 Nov 2010 10:38:07 -0000	1.1
+++ src/rsrv/caservertask.c	23 May 2013 09:16:42 -0000	1.4
@@ -37,6 +37,8 @@
 #include "dbEvent.h"
 #include "dbCommon.h"
 #include "epicsStdioRedirect.h"
+#include "epicsExit.h"
+#include "epicsString.h"
 
 #define epicsExportSharedSymbols
 #include "rsrv.h"
@@ -110,6 +112,15 @@
     status = bind ( IOC_sock, (struct sockaddr *) &serverAddr, sizeof ( serverAddr ) );
 	if ( status < 0 ) {
 		if ( SOCKERRNO == SOCK_EADDRINUSE ) {
+#ifndef vxWorks
+            const char* multiple_iocs = getenv("EPICS_ALLOW_MULTIPLE_IOCS");
+            if (multiple_iocs && epicsStrCaseCmp(multiple_iocs, "NO") == 0)
+            {
+                errlogPrintf ( "CAS: Default server port %d unavailable.\n" ,ca_server_port);
+                errlogPrintf ( "CAS: Probably already running an IOC on this computer.\n");
+                epicsExit(1);
+            }
+#endif
 			/*
 			 * enable assignment of a default port
 			 * (so the getsockname() call below will