ICMP Echo Reply
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The Echo Reply is an ICMP message generated in response to an ICMP Echo Request message, and is mandatory for all hosts and routers.
Message Format:
| 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Type = 0 | Code = 0 | Header Checksum | |||||||||||||||||||||||||||||
| Identifier | Sequence Number | ||||||||||||||||||||||||||||||
| Data ::: | |||||||||||||||||||||||||||||||
- Type and Code must be set to 0.
- The Identifier and Sequence Number can be used by the client to manage which Echo Requests are associated with the Echo Replies.
- The Data received by the Echo Request must be entirely included in the Echo Reply.
