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FC4B:29C4:7EA9:88BD:916E:FBA7:6D4C:3790

0000:0000:0000:0000:73F0:0064:02C1:000D

::::73F0:64:2C1:D

|00|01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26|27|28|29|30|31|  <- 32 Bits





 _______________________________________________________________________________________________


|           |           |                       |                                               |  |00|


|  Version  |  Length   |    Type Of Service    |                  Total Length                 |  |01|


|           |           |                       |                                               |  |02|


|___________|___________|_______________________|_______________________________________________|  |03|


|                                               |        |                                      |  |04|


|                Identification                 | Flags  |            Fragment Offset           |  |05|


|                                               |        |                                      |  |06|


|_______________________________________________|________|______________________________________|  |07|


|                       |                       |                                               |  |08|


|     Time To Live      |       Protocol        |                Header Checksum                |  |09|  <- 20 Bytes


|                       |                       |                                               |  |10|


|_______________________|_______________________|_______________________________________________|  |11|


|                                                                                               |  |12|


|                                         Source Address                                        |  |13|


|                                                                                               |  |14|


|_______________________________________________________________________________________________|  |15|


|                                                                                               |  |16|


|                                      Destination Address                                      |  |17|


|                                                                                               |  |18|


|_______________________________________________________________________________________________|  |19|





|                                                                                               |


|                                           Options                                             |


|                                                                                               |


|_______________________________________________________________________________________________|


|                                                                                               |


|                                           Options                                             |


|                                                                                               |


|_______________________________________________________________________________________________|


|                                                                                               |


|                                            Data                                               |


|                                                                                               |


|_______________________________________________________________________________________________|


   The options is not always a part of the IPv4 header

|00 |01 |02 |03 |04 |05 |06 |07 |


 _______________________________


|Precedence | D | T | R | 0 | 0 |


|___________|___|___|___|___|___|

00000001   1    ICMP	Internet Contol Message Protocol


00000010   2    IGMP	Internet Group Management Protocol


00000011   3    GGP	Gateway-to-Gateway Protocol


00000101   5    ST		Stream


00000110   6    TCP      	Transmission Control Protocol


00000111   7    UCL      	UCL


00001000   8    EGP     	External Gateway Protocol


00001001   9    IGP       	Interior Gateway Protocol


00001010   10  BNN-RCC-MON    BBN RCC Monitoring


00001011   11  NVP-II  	 Network Voice Protocol


00001100   12  PUP     	 PUP


00001101   13  ARGUS      	 ARGUS


00001110   14  EMCON       	 EMCON


00001111   15  XNET   	 Cross Net Debugger


00010000   16  CHAOS      	 Chaos


00010001   17  UDP        	 User Datagram Protocol


00010010   18  MUX         	 Multiplexing


00010011   19  DCN-MEAS     DCN Measurement Subsystems


00010100   20  HMP         	 Host Monitoring Protocol


00010101   21  PRM         	Packet Radio Measurement


00010110   22  XNS-IDP     	 XEROX NS IDP


00010111   23  TRUNK-1     	 Trunk 1


00011000   24  TRUNK-2     	 Trunk 2


00011001   25  LEAF-1      	 Leaf 1


00011010   26  LEAF-2    	 Leaf 2


00011011   27  RDP    	 Reliable Data Prococol


00011100   28  IRTP    	 Internet Reliable Transaction


00011101   29  ISO-TP4   	ISO Transport Protocol Class 4


00011110   30  NETBLT   	Bulk Data Transfer Protocol


00011111   31  MFE-NSP  	MFE Network Services Protocol


00100000   32  MERIT-INP 	MERIT Internodal Protocol


00100001   33  SEP    	Sequential Exchange Protocol


00111110   62  CFTP   	 CFTP


01000000   64  SAT-EXPAK	 SATNET and backroom EXPAK


01000001   65  MIT-SUBNET   MIT subnet support


01000010   66  RVD         	 MIT Remote Virtual Disk Protocol


01000011   67  IPPC        	 Internet Pluribus Packet Core


01000101   69  SAT-MON      SATNET Monitoring


01000111   71  IPCV        	 Internet Packet Core Utility


01001100   76  BR-SAT-MON   Backroom SATNET Monitoring


01001110   78  WB-MON    	 WIDEBAND Monitoring


01001111   79  WB-EXPAK  	 WIDEBAND EXPAK

unsigned short CalculateChecksum(


 const unsigned short *usBuf,


  int iSize


) {


   unsigned long usChksum=0;


     while (iSize>1)


     {


      usChksum += *usBuf++;


      iSize    -= sizeof(unsigned short);


     }


     if (iSize) usChksum += *(unsigned char*)usBuf;


      usChksum  = (usChksum >> 0x10) + (usChksum & 0xffff);


      usChksum += (usChksum >> 0x10);


     return (unsigned short)(~usChksum);


  }

|00|01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26|27|28|29|30|31|  <- 32 Bits





 _______________________________________________________________________________________________


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|  Version  |    Traffic Class      |                       Flow Label                          |


|           |                       |                                                           |


|___________|_______________________|___________________________________________________________|


|                                               |                       |                       |


|                 Payload Length                |      Next Header      |      Hop Limit        |


|                                               |                       |                       |


|_______________________________________________|_______________________|_______________________|


|__                                                                                           __|


|__                                       Source Address                                      __|


|__                                                                                           __|


|_______________________________________________________________________________________________|


|__                                                                                           __|


|__                                     Destination Address                                   __|


|__                                                                                           __|


|_______________________________________________________________________________________________|