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ICMP Type 0 Echo Reply

ICMP — Internet Control Message Protocol

The response to an ICMP Type 8 Echo Request.

The data received in the echo message must be returned in the echo reply message.

Source RFC 792.

Responses will have

  • Same identifier
  • Same sequence number
  • Same data
 0                   1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
┌───────────────┬───────────────┬───────────────────────────────┐
│   Type = 0    │   Code = 0    │          Checksum             │
├───────────────┴───────────────┼───────────────────────────────┤
│          Identifier           │        Sequence Number        │
├───────────────────────────────┴───────────────────────────────┤
│                             Data                              │
└───────────────────────────────────────────────────────────────┘

References

RFC 792: Internet Control Message Protocol | RFC Editor

RFC 1122: Requirements for Internet Hosts | RFC Editor

IANA: Internet Control Message Protocol (ICMP) Parameters

Last Modified • Tuesday, July 7, 2026. 6:20 pm UTC+00:00 • Commit: 699bb08