Protocol

ICMP

ICMPv6

Lab ready Full lab

ICMP/ICMPv6 carries control and error messages for IP: echo, unreachable, time exceeded, and (for v6) Neighbor Discovery. Operators filter it aggressively, yet PMTUD and many diagnostics still depend on it. Treat soft errors as signals, not noise.

Domains

Layers

Tags

diagnosticsechopmtudnd

Sources

  • RFC 792
  • RFC 4443 (ICMPv6)

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