Re: Gmail and China's GFW

[bk <chort0 () gmail com>]

On Mar 21, 2011, at 1:43 PM, Cal Leeming wrote:

> On Mon, Mar 21, 2011 at 8:39 PM, bk <chort0 () gmail com> wrote:
>
> On Mar 21, 2011, at 10:52 AM, Alien Chatter wrote:
>
> > $ sudo iptables -I INPUT -m string --algo bm --hex-string
> > '|476f6f676c6520496e63311830160603550403140f6d61696c2e676f6f676c652e636f6d30819f30|'
> > -j DROP
> >
> > Try it, you will get a connection timeout:
> >
> > $ curl --connect-timeout 60 https://mail.google.com/
> > curl: (28) SSL connection timeout
> >
> > The same applies for Twitter, Facebook... Much more efficient than
> > DNS/IP blocking!
>
> Because searching for a bytestring in payload generates so much less load than just overriding a DNS result at the 
> recursive server (that users are forced to issue queries to) or a simply drop SYNs based on IP header value that 
> routers/firewalls are optimized for...
>
> I think you forgot your coffee this morning.  It's not just for aliens you know.
>
> --
> chort
>
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> I think what he meant by efficient, was that if their sites ever get re-numbered or more end nodes are added (which 
> may or may not be that often), then this would still catch the connections.
>
> Imho, I think it'd be better to just have a script checking for it, but nether the less, it's a cute approach 
> (albeit, probably not usable in a production environment).

It's "efficient" in that humans get to be lazy.  It's not efficient as far as hardware resource utilization.

--
chort


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