diff --git a/src/common/network/dhcp.c b/src/common/network/dhcp.c
index ed557bd..b58107c 100644
--- a/src/common/network/dhcp.c
+++ b/src/common/network/dhcp.c
@@ -22,7 +22,7 @@ void DHCP_request_send(packet_t *pPacket, uint32_t dhcp_msg_type, uint8_t *mac_a
 	DHCP dhcp;
 	dhcp_opt_hdr_t *pOpt_hdr;
 	uint32_t size;
-	uint32_t magic = 0x63825363;
+	uint32_t magic = DHCP_MAGIC_COOKIE;
 	uint32_t option_size;
 	
 	DHCP *pDHCP = &dhcp;
@@ -161,6 +161,6 @@ void DHCP_request_send(packet_t *pPacket, uint32_t dhcp_msg_type, uint8_t *mac_a
 		default:
 		break;
 	}
-	UDP_create(pPacket, inet_addr_src, 68, inet_addr_dst, 67, (uint8_t*)&dhcp, sizeof(DHCP) - sizeof(dhcp_option_t) + option_size);
+	UDP_create(pPacket, inet_addr_src, 68, inet_addr_dst, 67, (uint8_t*)&dhcp, sizeof(DHCP));
 }
 
diff --git a/src/common/network/dhcp.h b/src/common/network/dhcp.h
index 558bce6..b4f7f4d 100644
--- a/src/common/network/dhcp.h
+++ b/src/common/network/dhcp.h
@@ -31,6 +31,7 @@ typedef struct _sDHCP
 
 } __attribute__ ((__packed__)) DHCP;
 
+#define DHCP_MAGIC_COOKIE		0x63825363
 
 #define	DHCP_BOOTREQUEST		1		// request.
 #define	DHCP_BOOTREPLY			2 		// reply.