diff --git a/bindings/ruby/rbsigar.c b/bindings/ruby/rbsigar.c
index 3030da8f..7bfc7a7d 100644
--- a/bindings/ruby/rbsigar.c
+++ b/bindings/ruby/rbsigar.c
@@ -682,6 +682,8 @@ static void Init_rbsigar_constants(VALUE rclass)
     RB_SIGAR_CONST_INT(IFF_PROMISC);
     RB_SIGAR_CONST_INT(IFF_ALLMULTI);
     RB_SIGAR_CONST_INT(IFF_MULTICAST);
+    RB_SIGAR_CONST_INT(IFF_SLAVE);
+    RB_SIGAR_CONST_INT(IFF_MASTER);
 
     RB_SIGAR_CONST_INT(NETCONN_CLIENT);
     RB_SIGAR_CONST_INT(NETCONN_SERVER);
diff --git a/include/sigar.h b/include/sigar.h
index 1de9dba5..a09ecebd 100644
--- a/include/sigar.h
+++ b/include/sigar.h
@@ -584,6 +584,7 @@ SIGAR_DECLARE(int) sigar_net_route_list_destroy(sigar_t *sigar,
 #define SIGAR_IFF_ALLMULTI    0x200
 #define SIGAR_IFF_MULTICAST   0x800
 #define SIGAR_IFF_SLAVE       0x1000
+#define SIGAR_IFF_MASTER      0x2000
 
 #define SIGAR_NULL_HWADDR "00:00:00:00:00:00"
 
diff --git a/src/sigar.c b/src/sigar.c
index 114c98b5..9ab00450 100644
--- a/src/sigar.c
+++ b/src/sigar.c
@@ -1550,6 +1550,7 @@ int sigar_net_interface_config_get(sigar_t *sigar, const char *name,
 #ifdef __linux__
         int is_mcast = flags & IFF_MULTICAST;
         int is_slave = flags & IFF_SLAVE;
+        int is_master = flags & IFF_MASTER;
         /*
          * XXX: should just define SIGAR_IFF_*
          * and test IFF_* bits on given platform.
@@ -1557,13 +1558,16 @@ int sigar_net_interface_config_get(sigar_t *sigar, const char *name,
          * for the flags we care about.
          *
          */
-        flags &= ~(IFF_MULTICAST|IFF_SLAVE);
+        flags &= ~(IFF_MULTICAST|IFF_SLAVE|IFF_MASTER);
         if (is_mcast) {
             flags |= SIGAR_IFF_MULTICAST;
         }
         if (is_slave) {
             flags |= SIGAR_IFF_SLAVE;
         }
+        if (is_master) {
+            flags |= SIGAR_IFF_MASTER;
+        }
 #endif
         ifconfig->flags = flags;
     }
diff --git a/src/sigar_format.c b/src/sigar_format.c
index b44c3a7f..ea7d5290 100644
--- a/src/sigar_format.c
+++ b/src/sigar_format.c
@@ -553,6 +553,12 @@ SIGAR_DECLARE(char *) sigar_net_interface_flags_to_string(sigar_uint64_t flags,
     if (flags & SIGAR_IFF_MULTICAST) {
         strcat(buf, "MULTICAST ");
     }
+    if (flags & SIGAR_IFF_SLAVE) {
+        strcat(buf, "SLAVE ");
+    }
+    if (flags & SIGAR_IFF_MASTER) {
+        strcat(buf, "MASTER ");
+    }
 
     return buf;
 }