diff --git a/TODO b/TODO
index fd87a76..2ef714c 100644
--- a/TODO
+++ b/TODO
@@ -2,4 +2,4 @@
  * Have one more look at IPv6 extension headers
  * Add support for type-1, type-2 routing headers
  * Add support for short form of IPv6 prefix in RA prefix option
- * MAC validation is yet to be added
+ * MAC validation is yet to be added [19-08-2013]
diff --git a/conf b/conf
index 682355a..a0af654 100644
--- a/conf
+++ b/conf
@@ -1,6 +1,6 @@
 BUFF_SIZE=1024
 
-IF_NAME=lo
+IF_NAME=eth0
 PK_DST_MAC=00:01:9B:04:03:3C
 
 ETHER_HEADER
diff --git a/help.c b/help.c
index 2fc9cf2..19d0e17 100644
--- a/help.c
+++ b/help.c
@@ -107,6 +107,41 @@ int32_t send_packet(const char *if_name, const char *dst_mac, const char *cp_buf
 	return -1;
 }
 
+/**
+ * @param	mac		The mac address that to be validated
+ *
+ * @return
+ *			0		Success
+ *			-1		Error
+ *
+ * @Description
+ *		Checks whether the given mac address is valid.
+ */
+int validate_mac(const char *mac) {
+	int i;
+
+	if (strlen(mac) != 17)
+		goto err;
+
+	for (i = 0; i < 17; i++) {
+		if ((((mac[i] >= 'A') && (mac[i] <= 'F')) ||
+				((mac[i] >= 'a') && (mac[i] <= 'f')) ||
+				((mac[i] >= '0') && (mac[i] <= '9')))
+				&& ((i+1) % 3 != 0))
+			continue;
+		else if ((mac[i] == ':') && ((i+1)%3 == 0))
+			continue;
+		else
+			goto err;
+	}
+	return 0;
+
+err:
+	PGEN_INFO("Mac validation failed");
+	PGEN_PRINT_DATA("%s\n", mac);
+	return -1;
+}
+
 /**
  * @param	dst		Destination pointer where the resulting mac address
  *					will be stored
@@ -125,6 +160,14 @@ int32_t mac_writer(char *dst, const char *src) {
     char ind;
     int32_t i, j = 0;
 
+	if (!dst || !src) {
+		PGEN_INFO("Arguments NULL check failed");
+		goto err;
+	}
+
+	if (validate_mac(src))
+		goto err;
+
     for (i = 0; i < 17; i++) {
         ind = src[i];
         if (ind >= '0' && ind <= '9')
@@ -137,13 +180,15 @@ int32_t mac_writer(char *dst, const char *src) {
             dst[j++] = (unsigned char) seg;
             seg = 0;
         }
-        else {
-			PGEN_INFO("mac_writer returns error");
-            return -1;
-		}
+        else
+			goto err;
     }
 	dst[j] = (unsigned char) seg;
     return 0;
+
+err:
+	PGEN_INFO("mac_writer returns error");
+	return -1;
 }
 
 /**
diff --git a/main.c b/main.c
index 56e0b62..47cee7f 100644
--- a/main.c
+++ b/main.c
@@ -127,7 +127,6 @@ int32_t main(int32_t argc, char **argv) {
 
 err:
 	PGEN_INFO("ERROR CASE");
-	PGEN_PRINT_DATA("Option: %s\tValue: %s\n", option, value);
 	fclose(fp);
 	/* free will accept NULL also */
 	free(cp_buff);