ICMP协议

最近更新时间:2018-01-30 16:12:01

ICMP 协议

ICMP协议是一种面向无连接的协议,属于网络层协议,主要用于在主机与路由器之间传递控制信息,包括报告错误、交换受限控制和状态信息等。当遇到IP数据无法访问目标、IP路由器无法按当前的传输速率转发数据包等情况时,会自动发送ICMP消息。ICMP包有一个8字节长的包头,其中前4个字节是固定的格式,包含8位类型字段,8位代码字段和16位的校验,后4个字节根据ICMP包的类型而取不同的值。

ICMP类型值及代码值

类型值 类型说明 代码值 代码说明
8 Echo 0 Echo request
0 Echo Reply 0 Echo reply
3 Destination Unreachable 0 Destination network unreachable
1 Destination host unreachable
2 Destination protocol unreachable
3 Destination port unreachable
4 Fragmentation required, and DF flag set
5 Source route failed
6 Destination 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 unreachable for TOS
13 Communication administratively prohibited
14 Host Precedence Violation
15 Precedence cutoff in effect
4 Source Quench 0 Source quench (congestion control)
5 Redirect Message 0 Redirect Datagram for the Network
1 Redirect Datagram for the Host
2 Redirect Datagram for the TOS & network
3 Redirect Datagram for the TOS & host
9 Router Advertisement 0 Router Advertisement
10 Router Solicitation 0 Router discovery/selection/solicitation
11 Time Exceeded 0 TTL expired in transit
1 Fragment reassembly time exceeded
12 Parameter Problem: Bad IP header 0 Pointer indicates the error
1 Missing a required option
2 Bad length
13 Timestamp 0 Timestamp
14 Timestamp Reply 0 Timestamp reply
15 Information Request 0 Information request
16 Information Reply 0 Information reply
17 Address Mask Reques 0 Address mask request
18 Address Mask Reply 0 Address mask reply
30 Traceroute 0 Information request

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