diff --git a/include/sigar.h b/include/sigar.h
index a00a447e..ebe7cfe6 100644
--- a/include/sigar.h
+++ b/include/sigar.h
@@ -477,7 +477,8 @@ enum {
     SIGAR_TCP_CLOSE_WAIT,
     SIGAR_TCP_LAST_ACK,
     SIGAR_TCP_LISTEN,
-    SIGAR_TCP_CLOSING
+    SIGAR_TCP_CLOSING,
+    SIGAR_TCP_UNKNOWN
 };
 
 typedef struct {
diff --git a/src/sigar.c b/src/sigar.c
index e53797b1..6a05868a 100644
--- a/src/sigar.c
+++ b/src/sigar.c
@@ -703,6 +703,7 @@ SIGAR_DECLARE(const char *)sigar_net_connection_state_get(int state)
         return "LISTEN";
       case SIGAR_TCP_CLOSING:
         return "CLOSING";
+      case SIGAR_TCP_UNKNOWN:
       default:
         return "UNKNOWN";
     }