- From: Andreas Petersson <andreas@sbin.se>
- Date: Tue, 19 Apr 2011 11:09:17 +0200
- To: "Poul-Henning Kamp" <phk@phk.freebsd.dk>, "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>
- Cc: Mark Nottingham <mnot@mnot.net>, Willy Tarreau <w@1wt.eu>, "Thomson, Martin" <Martin.Thomson@commscope.com>, Karl Dubost <karld@opera.com>
On Tue, 19 Apr 2011 07:53:33 +0000 "Poul-Henning Kamp" <phk@phk.freebsd.dk> wrote: > In message <8F735513-6A44-4043-B7DA-EAE1E2FD1A0D@mnot.net>, Mark Nottingham wri > tes: > > >> Forwarded: for=5.6.7.8:3456, for=8.9.1.2;by=4.5.6.7 > >> Forwarded: for=1.2.3.4:5678;by=4.3.2.1:3128;proto=https > > This format needs a strict definition to be unambigious. > > For instance, if the first proxy adds only "for" and the next adds > only "by", there is no way to tell if one or two proxies were > involved. One proxy should add one element, which is a list of key=values separated by semicolon. Two proxies: Forwarded: for=1.2.3.4, by=4.5.6.7 One proxy: Forwarded: for=1.2.3.4; by=4.5.6.7 Or do I miss something? > I still think it is a better idea that each proxy adds exactly one > element, and that the single element contains whatever information > the proxy is willing to disclose. Can you give an example of how such an element would look like? Only sending the IP-address of the client you are forwarding for would maybe be the cleanest, but there seems to be a need for disclosing other information too when proxying. That information would need to be connected to the forwarded-for somehow. E.g: Forwarded-For: 1.2.3.4, 5.6.7.8 X-Forwarded-By: 3.4.5.6 would be ambiguous. I am afraid that one will sooner or later see the need for standardizing also X-Fowarded-(By|Proto|Host ...) and doing that and keeping the format of Forwarded-For would be hard. I don't think it'd be a good situation if we had yet another way of disclosing such information, therefore maybe it's better to support all of them here? /Andreas Petersson
Received on Tuesday, 19 April 2011 09:10:25 UTC