MX

MX

[1] draft-cai-ssdp-v1-03 - Simple Service Discovery Protocol/1.0 ( ( 版)) <http://tools.ietf.org/html/draft-cai-ssdp-v1-03#section-4.2.1.1>

[2] RFC 7505 - A "Null MX" No Service Resource Record for Domains That Accept No Mail ( 版) <https://tools.ietf.org/html/rfc7505>