1. DNS/RFC/6891
Contents
https://tools.ietf.org/html/rfc6891
Extension Mechanisms for DNS (EDNS(0))
- EDNS0についての定義
OPT RRについての定義
One OPT pseudo-RR can be added to the additional data section of either a request or a response.
An OPT is called a pseudo-RR
- because it pertains to a particular transport level message and not to any actual DNS data.
OPT RRs shall never be cached, forwarded, or stored in or loaded from master files.
The quantity of OPT pseudo-RRs per message shall be either zero or one, but not greater.