Type 42
ICMPv4 Type 42 · Extended Echo Request
Recorded
IANA ICMP Type 42 Extended Echo Request (PROBE), defined in RFC 8335. ICMPv6 counterpart is Type 160.
RFC 8335 defines the ICMP Extended Echo Request used by the PROBE diagnostic utility. The value for ICMPv4 is 42. IANA lists Type 42 as Extended Echo Request, with code 0 for No Error. Distinct from classic Echo, which is Type 8.
What it supports
An exact assigned number in the ICMP catalogue, with its own diagnostic job: probe an interface without needing a reply from that same interface.
What it does not
Not classic ping (Type 8). Not ICMPv6 Type 160 collapsed into this plate. Not IANA port 42 or IP protocol 42. Not Adams.
ExactnessExact
Form42
UnitICMP type
Strengthhard
Hung26 September 2026