Re: Minimum HTTP version (was: Accept-Ranges: the controversy that wouldn't die)

Koen Holtman writes:
 > Shel Kaphan:
 > >
 > >In addition to knowing if there is a server somewhere in the chain that
 > >supports byte ranges, it would be useful to be able to tell what the
 > >minimum HTTP version is in a chain of servers.
 > The Via header allows, among other things, the detection of the
 > presence of 1.0 servers in the chain.
 > >--Shel
 > Koen.

It would, if it were there in earlier versions of the protocol.  In
1.0 all you get is mashed User-Agent headers and the occasional
Forwarded header, if you're lucky. It would be far more reliable to
make it mandatory for 1.1 servers to "report on their neighbors".

Here's a User-Agent header from today's logs:

Mozilla/2.02 (Win16; I)  via proxy gateway  CERN-HTTPD/3.0 libwww/2.17 Modified via PRD proxy gateway via Harvest Cache version 1.4pl2 via Harvest Cache version 1.4pl3

I guess you can "back out" the information by looking for "via" or
"forwarded" in the user-agent string, or looking for a "Forwarded"
header, and if either is present assume there's a 1.0 or earlier proxy in the
chain. That's fairly ugly and probably not very reliable though.


Received on Thursday, 6 June 1996 09:07:31 UTC