[BCP38]    Best Current Practice 38,
              <https://www.rfc-editor.org/info/bcp38>.
              At the time of writing, this BCP comprises the following:

              Ferguson, P. and D. Senie, "Network Ingress Filtering:
              Defeating Denial of Service Attacks which employ IP Source
              Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827,
              May 2000, <https://www.rfc-editor.org/info/rfc2827>.