[clug] browser connection question

Eyal Lebedinsky eyal at eyal.emu.id.au
Mon Aug 17 05:25:36 UTC 2015

On 17/08/15 10:49, David Deaves wrote:
>> First, I apologise for interrupting the less technical discussions going on...
>> I start firefox and have nothing open. I am observing the activity on my privoxy log.
>> I connect to DuckDuckGo and see that connection in the log.
>> Without any query I close the window, then even clear cookies and the cache.
>> About 3 minutes later I see a connection
>> 	"CONNECT duckduckgo.com:443 HTTP/1.1" 200 257620
>> The log shows activity without delay and the messages are timestamped anyway.
>> What is causing this? I expected the closed tab to be done with this site.
> Your browser is being helpful.  Setting up a SSL connection is costly, and
> HTTP/1.1 allows multiple requests over one connection.  So when you first
> connected to duckduckgo it opened the SSL connection, but rather than close it
> immediately only to have to open it again later, it keeps it open for future
> use.  After a period of no use it prunes the no longer required connection.
> The same is true of regular TCP connections, they are not as costly as SSL,
> but caching connections is still of value.

I understand caching, but do not see why a new connection is required when dropping
the idle connection - after all the connection is cached and alive already.

> Dave !


Eyal Lebedinsky (eyal at eyal.emu.id.au)

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