Learning python networking

[William Ray Wing]

On Jan 15, 2014, at 11:31 AM, Chris Angelico <rosuav at gmail.com> wrote:

> On Thu, Jan 16, 2014 at 3:25 AM, William Ray Wing <wrw at mac.com> wrote:
>> On Jan 15, 2014, at 7:52 AM, Chris Angelico <rosuav at gmail.com> wrote:
>>> One of the fundamentals of the internet is that connections *will*
>>> break. A friend of mine introduced me to Magic: The Gathering via a
>>> program that couldn't handle drop-outs, and it got extremely
>>> frustrating - we couldn't get a game going. Build your server such
>>> that your clients can disconnect and reconnect, and you protect
>>> yourself against half the problem; allow them to connect and kick the
>>> other connection off, and you solve the other half.
>> 
>> But note VERY carefully that this can open HUGE security holes if not done with extreme care.
>> 
>> Leaving a dangling connection (not session, TCP closes sessions) open is an invitation so bad things happening.
> 
> Not sure what you mean here. I'm assuming an authentication system
> that stipulates one single active connection per authenticated user
> (if you reauthenticate with the same credentials, it'll disconnect the
> other one on the presumption that the connection's been lost). In
> terms of resource wastage, there's no difference between disconnecting
> now and letting it time out, and waiting the ten minutes (or whatever)
> and then terminating cleanly. Or do you mean another user gaining
> access? It's still governed by the same authentication.
> 

I was assuming another user picking up the connection using sniffed credentials (and yes, despite all the work on ssh, not all man-in-the-middle attacks have been killed).

-Bill

> ChrisA
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