| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Version | IHL | Type of Service | Total Length | ||||||||||||||||||||||||||||
| Identification | Flags | Fragment Offset | |||||||||||||||||||||||||||||
| Time to Live | Protocol | Header Checksum | |||||||||||||||||||||||||||||
| Source IP Address | |||||||||||||||||||||||||||||||
| Destination IP Address | |||||||||||||||||||||||||||||||
| Options (optional) | |||||||||||||||||||||||||||||||
IP Header Contents
Version 4 IP version 4 Internet Header Length Number of 32-bit words in IP header; minimum value = 5 (20 bytes) & maximum value = 15 (60 bytes) Type of Service (PreDTRCx) --> Differentiated Services Precedence (000-111) 000 D (1 = minimize delay) 0 T (1 = maximize throughout) 0 R (1 = maximize reliability) 0 C (1 = minimize cost) 1 = ECN capable x (reserved and set to 0) 1 = congestion experienced Total Length Number of bytes in packet; maximum length = 65,535 Flags (xDM) x (reserved and set to 0) D (1 = Don't Fragment ) M( 1= More Fragment ) Fragment Offset Position of this fragment in the original datagram, in units of 8 bytes Protocol 1 ICMP 17 UDP 57 SKIP 2 IGMP 47 GRE 88 EIGRP 6 TCP 50 ESP 89 OSPF 9 IGRP 51 AH 115 L2TP Header Checksum Covers IP header only Addressing NET_ID RFC 1918 PRIVATE ADDRESSES 0 - 127 Class A 10.0.0.0 -10.255.255.255 128 - 191 Class B 172.16.0.0 - 172.31.255.255 192 - 223 Class C 192.168.0.0 - 192.168.255.255 224 - 239 Class D ( multicast ) 240 - 255 Class E ( experimental ) HOST_ID
255 BroadcastOptions (0-40 bytes; padded to 4-byte boundary) 0 End of Options list 68 Timestamp 1 No operation (pad) 131 Loose source route 7 Record route 137 Strict source route