Posted by osfwofujro on 09/07/05 00:12

Benjamin Niemann wrote:

>osfwofujro wrote:
>
>
>
>>When I connect to a webpage the page downloads on to my computer. When
>>the page has finished downloading, am I correct in thinking that the
>>connection between me and the web server terminates?
>>
>>
>
>Not necessarily. HTTP/1.1 knows 'keep-alive': if both sides (client and
>server, and perhaps proxies inbetween) support it, the connection will be
>kept open and be reused for more request. This can significantly improve
>page loading times (e.g. with lots of graphics), because the TCP handshake
>to initiate a connection does not have to be performed for every
>document/media object.
>
>
>
Thanks. Is there a way to find out if the webpage uses keep-alive? Say
by looking in the source?

>>And then if I click on another link in the same site or refresh the
>>page, then I reconnect from scratch again?
>>
>>
>
>Only if your at least one of the parties involved (client, server, proxies)
>does not support keep-alive or all connection have been closed after a
>certain timeout.
>
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>>And that the webpage knows
>>who I am (say if it's webmail) because of the cookie?
>>
>>
>
>That is just one of several possibilities. Others are session IDs in the
>query part of the URL (...?SID=3487387...), the referer header, your IP
>address or the ETag header could be abused for this. The latter three are
>all too fragile to be used e.g. for session management as it's used for a
>webmail application. Cookies or query strings are commonly used for this.
>
>
>
>>IOW, once the page has downloaded, the link between me and the website
>>is over - until I request another page/graphic/text on that site?
>>
>>
>
>see above
>
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>

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