Re: p1: Via and gateways

Willy Tarreau <w@1wt.eu> Sat, 20 April 2013 06:25 UTC

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Date: Sat, 20 Apr 2013 08:23:39 +0200
From: Willy Tarreau <w@1wt.eu>
To: Mark Nottingham <mnot@mnot.net>
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Subject: Re: p1: Via and gateways
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On Sat, Apr 20, 2013 at 02:07:11PM +1000, Mark Nottingham wrote:
> 
> p1 Section 2.3 says:
> 
> > However, an HTTP-to-HTTP gateway that wishes to interoperate with third-party HTTP servers must conform to HTTP user agent requirements on the gateway's inbound connection and must implement the Connection (Section 6.1) and Via (Section 5.7.1) header fields for both connections.
> 
> This means that accelerators and CDNs MUST generate a Via header on the outbound connection. This isn't widely practiced, and I'm not sure it's necessary. Comments?

I know no load-balancer which does it anyway. Especially in hosted
environments where it is desired that the infrastructure is as much
transparent to the hosted servers as possible.

I must say I never understood the rationale behind Via because for
incoming traffic we don't care and for outgoing traffic we don't
want to disclose to the world our inside details.

Another example of a MUST which makes people think that MUSTs are at user
option I think.

Willy