* [1] https://tools.ietf.org/html/rfc952
* [2] https://tools.ietf.org/html/rfc921
* [3] https://tools.ietf.org/html/rfc1123#page-13
* [1] https://tools.ietf.org/html/rfc952
* [2] https://tools.ietf.org/html/rfc921
* [3] https://tools.ietf.org/html/rfc1123#page-13