diff --git a/common/JackNetInterface.cpp b/common/JackNetInterface.cpp
index 45b9f507..d8562a05 100644
--- a/common/JackNetInterface.cpp
+++ b/common/JackNetInterface.cpp
@@ -477,7 +477,7 @@ namespace Jack
         int rx_bytes = Recv(fParams.fMtu, MSG_PEEK);
 
         if ((rx_bytes == 0) || (rx_bytes == SOCKET_ERROR)) {
-            // O bytes considered an error (lost connection)
+            // 0 bytes considered an error (lost connection)
             return SOCKET_ERROR;
         }
 
diff --git a/common/JackNetTool.h b/common/JackNetTool.h
index e78b4ea5..375aa376 100644
--- a/common/JackNetTool.h
+++ b/common/JackNetTool.h
@@ -637,7 +637,11 @@ namespace Jack
 
             for (uint port_index = 0; port_index < port_num; port_index++) {
                 // Use -1 when port is actually connected on other side
-                fPortBuffer[*active_port_address] = (sample_t*)-1;
+                if (*active_port_address >= 0 && *active_port_address < fNPorts) {
+                    fPortBuffer[*active_port_address] = (sample_t*)-1;
+                } else {
+                    jack_error("ActivePortsFromNetwork: incorrect port = %d", *active_port_address);
+                }
                 active_port_address++;
             }
         }