ICMP protocol and analysis of packet capture

ICMP protocol and analysis of packet capture

The Internet Message Control Protocol (ICMP) specifies a variety of message types, the purpose of which is to manage the network.
ICMP messages are divided into error messages, request messages and response messages.
General ICMP packet format
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ICMP packet type field and code field
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Wirehark packet capture analysis
Data link layer
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Network layer

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1. Response request
ping command: response request (Type = 8) and response request (Type = 0)
2. Time stamp:
time stamp request message (Type = 13) time stamp response message (Type = 14) for testing The transmission time of a data packet back and forth between two hosts.

3 important types:

Route advertisement (router advertisement) and route selection (router selection): Type 9 and Type 10 respectively, they are used in ICMP Route Discovery Protocol (IRDP). IRDP protocol is used in some operating systems to discover local routers

Redirection: ICMP type 5 is used by routers to notify the host to go to the gateway of the specified target, which is another router on the data link.

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Origin blog.csdn.net/qq_43710889/article/details/108858648