diff --git a/src/core/mac/mac.cpp b/src/core/mac/mac.cpp
index 611aabe3e..d9fda4bf6 100644
--- a/src/core/mac/mac.cpp
+++ b/src/core/mac/mac.cpp
@@ -106,7 +106,8 @@ Mac::Mac(ThreadNetif &aThreadNetif):
         mExtAddress.m8[i] = otPlatRandomGet();
     }
 
-    mExtAddress.m8[0] &= ~1; // always remove multicast bit
+    mExtAddress.SetGroup(false);
+    mExtAddress.SetLocal(true);
 
     memset(&mCounters, 0, sizeof(otMacCounters));
 
diff --git a/src/core/mac/mac_frame.hpp b/src/core/mac/mac_frame.hpp
index c3b964abf..45cfe26df 100644
--- a/src/core/mac/mac_frame.hpp
+++ b/src/core/mac/mac_frame.hpp
@@ -81,6 +81,36 @@ typedef otShortAddress ShortAddress;
 class ExtAddress: public otExtAddress
 {
 public:
+    /**
+     * This method sets the Group bit.
+     *
+     * @param[in]  aLocal  TRUE if group address, FALSE otherwise.
+     *
+     */
+    void SetGroup(bool aGroup) {
+        if (aGroup) {
+            m8[0] |= kGroupFlag;
+        }
+        else {
+            m8[0] &= ~kGroupFlag;
+        }
+    }
+
+    /**
+     * This method sets the Local bit.
+     *
+     * @param[in]  aLocal  TRUE if locally administered, FALSE otherwise.
+     *
+     */
+    void SetLocal(bool aLocal) {
+        if (aLocal) {
+            m8[0] |= kLocalFlag;
+        }
+        else {
+            m8[0] &= ~kLocalFlag;
+        }
+    }
+
     /**
      * This method converts an IPv6 Interface Identifier to an IEEE 802.15.4 Extended Address.
      *
@@ -88,6 +118,13 @@ public:
      *
      */
     void Set(const Ip6::Address &aIpAddress);
+
+private:
+    enum
+    {
+        kGroupFlag = 1 << 0,
+        kLocalFlag = 1 << 1,
+    };
 };
 
 /**