In section 5, there is a discussion of SERVFAIL returns from broken DNS
servers (which I've seen myself in production). That could use a one-sentence
clarification that the problem is the DNS server only having A records for
an address, and returning SERVFAIL rather than "no data" when asked for AAAA
records.
We all know who the offender is, and those of us who use Sendmail already
know why 'WorkAroundBrokenAAAA' exists. I'll let somebody with more
RFC-writing
experience than I decide if package-specific "If you run the XYZ MTA, do THIS
to work around it, if you run the ABC DNS server, upgrade to patch 1.15" info
should be included in an "operational requirements" RFC. RFC1912 mentions
specific releases of BIND, RFC2010 doesn't.
i don't think it necessary/required to list the broken implementation.
i know of a couple of products that behave badly (which is an IP load
balancing box product), but i don't think i can cover every broken
implementations.
itojun