$ ping 0000000000321.216.230.240 PING 0000000000321.216.230.240 (209.216.230.240) 56(84) bytes of data. 64 bytes from 209.216.230.240: icmp_seq=1 ttl=46 tim

$ ping 0000000000321.216.230.240 PING 0000000000321.216.230.240 (209.216.230.240) 56(84) bytes of data. 64 bytes from 209.216.230.240: icmp_seq=1 ttl=46 time=142 ms Platform-specific syntax, excellent. That sure makes it sound more consistent. You're right that you need to canonicalize addresses as part of comparing their textual forms. It's well-documented -- at least in v6 -- that you need to do that. > Unfortunately, Node does not include a method for normalizing an address. That sounds like a Node problem. In C you can do it via getnameinfo(getaddrinfo()) or inet_ntop(inet_pton()).