My Secure Dream laptop

In his case and by his reasoning, making him sit in the comfy chair would probably be more sever than mere waterboarding, and would enrage him and force him to say something naughty.

Or Green Xenon could be the next John Patrick Bedell.

It is kind of like ARP but is coming from DHCP. Only the local router=20 needs to know which address it assigned to your laptop.

Most IP addresses are "globally unique" - that is, there can only be one active computer on the Internet with each specific IP address. Web servers, email servers, etc. which are intended to be reachable from any location on the Internet need to have a unique IP address and be "routable". You have to have a specific authorization to use such an address (e.g. you get one from your ISP, who was authorized to route and manage a whole block of these addresses).

Since there are only 2 billion IP (version 4) addresses possible (32 bits' worth), the Internet is running out of such addresses.

A small portion of the IP address space was set aside, many years ago, as "private, non-routable". Addresses of the form 192.168.xxx.yyy,

Anyone can set up a "private" network using these network numbers... you don't have to register for them in advance. As a result, there are many millions of small networks (e.g. homes and businesses) which use these network addresses. Any consumer-grade wireless access point/router is very probably set up to hand out these sorts of addresses to systems within its household network.

Because these addresses aren't unique and aren't registered, there's no way for a system using one of these to _directly_ connect to a system out on the Internet... there would be no way to route the response packets back to your laptop. Connections to the Internet must be made indirectly.

What usually happens is something called "network address translation" (NAT) or "IP masquerading". In effect, every time your laptop (on a private network) sends a packet out to the Internet, the access-point router automatically substitutes its own IP address (which is unique and routable) for the "private" IP address your laptop is using. The packets sent back in response by the site you're browsing reach the access-point router, and the router accepts the packet and then forwards it to your laptop. The router can do this for dozens of "private" IP addresses simultaneously. In effect, the router is acting as a "proxy" for your laptop.

So, from the point of view of systems out on the Internet, all of the web-surfing activity appears to originate from a single IP address - that of the access-point router - and this traffic can be traced back to that one system.

Not true. It just must not be globally visible. There are address=20 blocks set aside for "local" use. If you have a home router=20 (and most DSL modems are such) it issues local home addresses in the=20 reserved 192.168.*.* local user address space.

There are some large private networks on 10.168.*.* as well

The (ISP's) server must have a DNS translation address that is reachable.= =20 Not so much the home network.

Make that not quite 4 billion, and consider that even shoes will have=20 addresses in not too many years and the push to IPv6 is obvious.

Making my point for me.

This is also part of why the US is being obstinately slow to move to=20 IPv6. The other part is billions of deployed infrastructure; much of=20 which is not very programmable in the necessary ways.

More often the ISP address block, not really routers. More like = connection=20 point clusters.