Re: Persistent and Keep-Alive in HTTP/1.1

At 02:50 AM 5/2/96 -0700, Roy T. Fielding wrote:
>> I still don't understand the point of having both Connection:
>> Persistent and Connection: Keep-Alive (not to mention "Connection:

>The fear was that some existing 1.0 clients may be sending keep-alive
>to a proxy server that doesn't understand Connection, which would then
>erroneously forward it to the next inbound server, which would establish
>the keep-alive connection and result in a dead 1.0 proxy waiting for the
>close on the response.  The result is that 1.0 clients must be prevented
>from using keep-alive when talking to proxies.
>[...]
>  1) Introduce a new keyword (persist) which is declared to be valid
>     only when received from an HTTP/1.1 message.

Another option would be to define a rule for client like:

"Send 'Connection: keep-alive' to origin servers, and 'Connection: persist'
with a 'Presist: <hostname>' to proxies"

Then 1.0 servers could still do persistent connections with 1.1 clients
without being upgraded.  And no version number-specific logic is necessary.

I have not heard of ANY 1.0 client sending Connection: headers to proxies
(except internal builds here at Spyglass where we first encountered the dead
proxy bug), so I think the above is a safe thing to do.

-----
the Programmer formerly known as Dan          
                                     http://www.spyglass.com/~ddubois/