In message <alpine.OSX.2.11.1608092140330.1678@ary.local>, "John R Levine" writes: > > RFC2671/RFC6891 has > > > > Z > > Set to zero by senders and ignored by receivers, unless modified > > in a subsequent specification. > > > > which resulted in 2% of deployed nameservers just copying reserved > > bits to the reply or 3% of nameservers not answering because a > > reserved bit is set. > > I suppose, but how many of the people who wrote the broken code would have > paid attention if it said YOU MUST SET THE BIT TO ZERO AND THEN IGNORE IT > YOU MORON. We will never know. "MUST be set to zero by senders and MUST be ignored by receivers, unless modified in a subsequent specification." would have caught those that scan for MUST, SHOULD and MAYs. At the moment we have draft-ietf-dnsop-no-response-issue-03 to try and clean up the mess out there. I'm waiting on Tim for promised feedback before I publish -04. Mark > Regards, > John Levine, johnl@xxxxxxxxx, Taughannock Networks, Trumansburg NY > Please consider the environment before reading this e-mail. -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka@xxxxxxx