Crackers and correlations

[Monty J. Harder]

"Gerald Combs" <gerald at ethereal.com> wrote:

> There's also "port knocking": http://www.portknocking.org/ .  In order
> for the firewall to open up port 22, you would have to send a special
> sequence of packets, e.g. attempt to connect to a specific combination
> of ports in a specific order.

  It's an interesting idea, but I think it's in the category of 'security
through obscurity'.  I think it would be cleaner to just send a UDP packet,
containing within it certain authentication information (including a
timestamp), digitally signed with a private key, that would give pretty high
confidence that you are legit before the TCP socket ever is opened.