IP & network

IP addresses are allocated through regional registries, and their records tell you who to contact when something goes wrong. These guides explain how to read that registration data and how to interpret ping and other reachability tests without being misled by filtering.

Ping, ICMP and what "unreachable" really meansupdated 26 October 2026
What ping measures, why a host that doesn't answer may be healthy, how to read packet loss, round-trip time and TTL, and why blocking all ICMP breaks things.
Reading IP Whois and RDAP results: owner, network and abuse contactupdated 26 October 2026
How IP addresses are allocated through the regional registries, what each field in an IP Whois/RDAP record means, and how to report abuse so it gets acted on.