Cacheability of 421 (Misdirected Request)

[Vasiliy Faronov <[e-mail]>]

Hi,

RFC 7540 Section 9.1.2 says that responses with status code 421
(Misdirected Request) are cacheable by default. I think this is wrong.
HTTP cache key is based on the request URI, so if a client were to
cache a 421 response, it would then use this cached 421 to satisfy
further requests to the same URI, before it has a chance to connect to
the right server.

I think the paragraph about cacheability should be removed, so that
the general "not by default" rule applies from RFC 7231 Section 6.1.
Or maybe even rewritten to say "Responses with the 421 status code
MUST NOT be stored by a cache," as in RFC 6585.

Should I report an erratum, or am I missing something?


-- 
Vasiliy