
INTERNET CONTROL MESSAGE PROTOCOL
ICMP is a networking protocol developed to analyse the connectivity between source and destination hosts.
The structure of ICMP datagram as follows
- Data (32 bytes by default)
- Sequence No: – Since it is sending data repeatedly, ICMP itself assings a sequence number to identify the segment of data
- Identifier – It is very close to port number. An identifier is assinged on each echo packets from the begining till the end of all sequence of data
- Checksum – Used for error detection
- Packet Type – To identify what type of ICMP packet
- Code – There are different codes for each type of ICMP packet.
The following content will gives you clearity about different Packet Types and what are the different codes for each Packet Types
Type |
Code /Name |
0 | Echo Reply |
3 | Destination Unreachable |
0 Network Unreachable | |
1 Host Unreachable | |
2 Protocol Unreachable | |
3 Port Unreachable | |
4 Fragmentaiton required, and DF set | |
5 Source Rooute Failed | |
6 Destionation Network Unknown | |
7 Destination Host Unknown | |
8 Source Host Isolated | |
9 Network Administratively Prohibited | |
10 Host Administratively Prohibited | |
11 Network Unreachable for TOS | |
12 Host Unreacheable for TOS | |
13 Communication Administratively Prohibited | |
4 | Source Quench |
5 | Redirect |
0 Redirect Datagram for the Network | |
1 Redirect Datagram for the Host | |
2 Redirect datargram for the TOS & Network | |
3 Redirect Datagram for the TOS & Host | |
8 | Echo |
9 | Router Advertisement |
10 | Router Selection |
11 | Time Exceeded |
0 TTL Exceeded | |
1 Fragment Reassembly Time Exceeded | |
12 | Parameter Problem |
0 Pointer Problem | |
1 Missing a Required Operand | |
2 Bad Length | |
13 | Timestamp |
14 | Timestamp Reply |
15 | Information Request |
16 | Information Reply |
17 | Address Mask Request |
18 | Address Mask Reply |
30 | Traceroute |
Leave a Reply