RFC Errata
RFC 1034, "Domain names - concepts and facilities", November 1987
Source of RFC: LegacyArea Assignment: int
Errata ID: 5316
Status: Held for Document Update
Type: Technical
Publication Format(s) : TEXT
Reported By: Mukund Sivaraman
Date Reported: 2018-03-31
Held for Document Update by: Warren Kumari (Ops AD)
Date Held: 2018-04-09
Section 4.3.3 says:
A * label appearing in a query name has no special effect, but can be used to test for wildcards in an authoritative zone; such a query is the only way to get a response containing RRs with an owner name with * in it. The result of such a query should not be cached.
It should say:
A * label appearing in a query name has no special effect, but can be used to test for wildcards in an authoritative zone; such a query is the only way to get a response containing RRs with an owner name with * in it. The result of such a query should not be used to synthesize RRs.
Notes:
It is perfectly OK for an RR with a wildcard label '*' to be cached as long as it's not used to synthesize any RRs on a caching resolver. The DNS implementations BIND and Unbound both cache such RRsets with wildcard label in the owner name.
WK (OpsAD): Please see thread https://www.ietf.org/mail-archive/web/dnsop/current/msg22563.html for additional information.