Firewall question

[Patrick O'Callaghan]

On Thu, 2008-05-15 at 12:42 +0100, Anne Wilson wrote:
> In another thread Tim Evans said:
> 
> You can, however, configure iptables to *allow* only a specified list of
> IP addresses (i.e., the ones you approve of).
> 
> This set me wondering.  If you use wifi hotspots to collect mail, for 
> instance, you have no idea what IPs you will be using.  Is there any way that 
> the system can recognise the computer rather than the IP?  I'm guessing it 
> must be possible, as my on-line bank knows immediately if I use a computer 
> that I haven't used before.

You collect mail by connecting from your machine to a server, so
firewall rules that block *incoming* connections won't affect you.

Recognizing the computer rather than the IP is not a firewall-level
question (more correctly: it's not a packet-filter level question, which
amounts to the same thing for most people). As others have pointed out,
this is one of the things cookies are used for.

poc