Please document syntax and semantics of NO_PROXY environment variable. #1208
Description
Curl's man page about NO_PROXY:
list of host names that shouldn't go through any proxy. If set to a asterisk '*' only, it matches all hosts.
Curl's manual about NO_PROXY:
If the host name matches one of these strings, or the host is within the domain of one of these strings, transactions with that node will not be proxied.
Description in the manual lacks information about asterisk and description in the man page should use phrasing from the manual which is more specific than the general list of host names phrase used.
In addition, even description from the manual is not specific enough. From https://curl.haxx.se/mail/archive-2007-11/0043.html :
From: Daniel Stenberg <daniel_at_haxx.se>
Date: Wed, 14 Nov 2007 23:33:52 +0100 (CET)
On Wed, 14 Nov 2007, Peter Love wrote:Is there an RFC which describes NO_PROXY usage?
Not that I'm aware of. When I implemented it (many years ago), I just checked
how other tools were documented to treat it and cloned that behavior.
It seems that behavior was cloned but not the documentation which is very unfortunate taking into consideration that curl's behavior is very often the informal specification of many aspects of dealing with HTTP.
The documentation should answer at least the following questions:
- Should values be fully qualified domain names (FQDN) to match exact domain? If one wants to match
example.comshould the value beexample.comorexample.com.(trailing dot) or either is allowed? - How to specify subdomains, with the dot at the beginning, with asterisk and the dot or nothing is required (subdomains are matched by default)?
- Do subdomains on any level match;
.example.commatchfoo.example.comandfoo.bar.example.comand so forth? - Is it possible to match any subdomain without matching parent domain; to match any
*.example.combut notexample.com?