diff --git a/checkin_notes b/checkin_notes
index dfcb07ef06..1924c9db04 100755
--- a/checkin_notes
+++ b/checkin_notes
@@ -14184,3 +14184,13 @@ David  2 Dec 2005
 
     lib/
         shmem.C
+        
+Rom    4 Dec 2005
+    - Bug Fix: Verify we are actually talking with a BOINC core client
+        before declaring a connection successful.
+        
+    client/
+        gui_rpc_server_ops.C
+    lib/
+        gui_rpc_client.C, .h
+        gui_rpc_client_ops.C
diff --git a/client/gui_rpc_server_ops.C b/client/gui_rpc_server_ops.C
index c8b2c0d3ef..ce5b0f56ef 100644
--- a/client/gui_rpc_server_ops.C
+++ b/client/gui_rpc_server_ops.C
@@ -74,6 +74,12 @@ void GUI_RPC_CONN::handle_auth2(char* buf, MIOFILE& fout) {
     auth_needed = false;
 }
 
+static void handle_get_client_time(MIOFILE& fout) {
+    fout.printf("<client_time>\n");
+    fout.printf("<time>%f</time>\n", dtime());
+    fout.printf("</client_time>\n");
+}
+
 static void handle_get_project_status(MIOFILE& fout) {
     unsigned int i;
     fout.printf("<projects>\n");
@@ -743,6 +749,8 @@ int GUI_RPC_CONN::handle_rpc() {
     MFILE m;
     char* p;
     int major_version;
+    int minor_version;
+    int release;
     mf.init_mfile(&m);
 
     SCOPE_MSG_LOG scope_messages(log_messages, CLIENT_MSG_LOG::DEBUG_GUIRPC);
@@ -764,6 +772,8 @@ int GUI_RPC_CONN::handle_rpc() {
     // get client version.  not used for now
     //
     parse_int(request_msg, "<major_version>", major_version);
+    parse_int(request_msg, "<minor_version>", minor_version);
+    parse_int(request_msg, "<release>", release);
 
     mf.printf(
         "<boinc_gui_rpc_reply>\n"
@@ -784,6 +794,8 @@ int GUI_RPC_CONN::handle_rpc() {
 
     // operations that require authentication for non-local clients start here
 
+    } else if (match_tag(request_msg, "<get_client_time")) {
+        handle_get_client_time(mf);
     } else if (match_tag(request_msg, "<get_state")) {
         gstate.write_state_gui(mf);
     } else if (match_tag(request_msg, "<get_results")) {
diff --git a/lib/gui_rpc_client.C b/lib/gui_rpc_client.C
index 0623c17a93..363c78d643 100644
--- a/lib/gui_rpc_client.C
+++ b/lib/gui_rpc_client.C
@@ -52,9 +52,16 @@
 using std::string;
 using std::vector;
 
-RPC_CLIENT::RPC_CLIENT() {}
+RPC_CLIENT::RPC_CLIENT() {
+    client_major_version = 0;
+    client_minor_version = 0;
+    client_release = 0;
+}
 
 RPC_CLIENT::~RPC_CLIENT() {
+    client_major_version = 0;
+    client_minor_version = 0;
+    client_release = 0;
     close();
 }
 
@@ -70,6 +77,7 @@ void RPC_CLIENT::close() {
 }
 
 int RPC_CLIENT::init(const char* host) {
+    double client_time = 0.0;
     int retval;
 	memset(&addr, 0, sizeof(addr));
     addr.sin_family = AF_INET;
@@ -107,6 +115,15 @@ int RPC_CLIENT::init(const char* host) {
             return ERR_CONNECT;
         }
     }
+
+    // Are we really talking to a BOINC core client.
+    if (get_client_time(client_time)) {
+        return ERR_RETRY;
+    }
+    if ((client_time == 0.0) && ((0 == client_major_version) && (0 == client_minor_version) && (0 == client_release))) {
+        return ERR_RETRY;
+    }
+
     return 0;
 }
 
@@ -151,6 +168,7 @@ int RPC_CLIENT::init_asynch(const char* host, double _timeout, bool _retry) {
 int RPC_CLIENT::init_poll() {
     fd_set read_fds, write_fds, error_fds;
     struct timeval tv;
+    double client_time = 0.0;
     int retval;
 
     FD_ZERO(&read_fds);
@@ -177,6 +195,12 @@ int RPC_CLIENT::init_poll() {
                 BOINCTRACE("asynch error: %d\n", retval);
                 return retval;
             }
+            if (get_client_time(client_time)) {
+                return ERR_RETRY;
+            }
+            if ((client_time == 0.0) && ((0 == client_major_version) && (0 == client_minor_version) && (0 == client_release))) {
+                return ERR_RETRY;
+            }
             return 0;
         } else {
             BOINCTRACE("init_poll: get_socket_error(): %d\n", retval);
diff --git a/lib/gui_rpc_client.h b/lib/gui_rpc_client.h
index e293e8e087..8a5b434ab0 100644
--- a/lib/gui_rpc_client.h
+++ b/lib/gui_rpc_client.h
@@ -520,6 +520,7 @@ public:
     int init_poll();
     void close();
     int authorize(const char* passwd);
+    int get_client_time(double& client_time);
     int get_state(CC_STATE&);
     int get_results(RESULTS&);
     int get_file_transfers(FILE_TRANSFERS&);
diff --git a/lib/gui_rpc_client_ops.C b/lib/gui_rpc_client_ops.C
index 83674260d8..270f46f453 100644
--- a/lib/gui_rpc_client_ops.C
+++ b/lib/gui_rpc_client_ops.C
@@ -886,6 +886,26 @@ void LOOKUP_WEBSITE::clear() {
 
 /////////// END OF PARSING FUNCTIONS.  RPCS START HERE ////////////////
 
+int RPC_CLIENT::get_client_time(double& client_time) {
+    char buf[256];
+    RPC rpc(this);
+    int retval;
+
+    client_time = 0;
+
+    retval = rpc.do_rpc("<get_client_time/>\n");
+    if (retval) return retval;
+
+    while (rpc.fin.fgets(buf, 256)) {
+        if (match_tag(buf, "</client_time>")) break;
+        else if (parse_int(buf, "<client_major_version>", client_major_version)) continue;
+        else if (parse_int(buf, "<client_minor_version>", client_minor_version)) continue;
+        else if (parse_int(buf, "<client_release>", client_release)) continue;
+        else if (parse_double(buf, "<time>", client_time)) continue;
+    }
+    return 0;
+}
+
 int RPC_CLIENT::get_state(CC_STATE& state) {
     char buf[256];
     PROJECT* project = NULL;
@@ -893,9 +913,6 @@ int RPC_CLIENT::get_state(CC_STATE& state) {
     int retval;
 
     state.clear();
-    client_major_version = 0;
-    client_minor_version = 0;
-    client_release = 0;
 
     retval = rpc.do_rpc("<get_state/>\n");
     if (retval) return retval;