[H-GEN] Networking portables...

[Anthony Towns]

Hello world,

I've been trying to figure out a nice way of getting sapphire (my laptop)
setup so that I can more or less just plug it into a network (be it home,
work, uni, humbug, or elsewhere) and have it "just work".

This means things like exim automatically knowing where the nearest relay
is, and netscape/lynx just using the right proxy (without having to click
here and click there all the time to tell it), having it just know its IP 
address, getting remote printers to become "lp", and whatever else.

The most obvious solution is "do it all locally", and write a script that
lets you type "network_at home" or "network_at work" and have it just set
everything up itself. That's suboptimal because it involves actual typing
(which I'd like to avoid). But it would, at least, work.

My other thought essentially requires a server at all of the above places 
that tells sapphire everything it needs to know about the network it just
connected to. This is ideal, IMO, but it also seems to be non-trivial.

The first and most obvious thing to do is setup DHCP (or BOOTP) to get an
IP address. The Linux bootpd even copes with DHCP requests, so just using
dhcpcd on the laptop seems like it'd work pretty well. 

Unfortunately, dhcp doesn't seem like it'd work too well at humbug. For a 
start we want some security on who gets to connect (or at least, who gets
to be routed), and we also want to give out static IPs, but we don't want
to base that on everyone using the same ethernet address (network card).

One possible way around this, would be to forget the whole static IP deal
and just have a pool of dynamic allocated IPs that people can use. That'd
mean the network access scripts would have to be changed (for anyone with
a laptop, at any rate), but on the upside it would mean there wouldn't be
a worry about having more HUMBUG members than we've got IPs. Not quite so
wonderful is that it'd make it somthing of a pain to get to or from other 
computers on the humbug network, at least for laptops.

The next problem is telling netscape and friends where their proxies are.
There's not really too many options here, though -- you *have* to specify 
the name of your proxy, and you *can't* (afaict) change it automatically.
So you basically have to create a new name, and a TLD to go with it.

So on azure, I've got a DNS file that sets http-proxy.dynamic to point at
azure, and on the server at work, http-proxy.dynamic points at the server
itself. Then I can just set my proxies to http://http-proxy.dynamic:8080/ 
and have it work.

This does, however, require deciding on a port number for http proxies -- 
which will which will probably be a pain of its own when I try connecting 
to UQ, which uses port 80, instead of 8080.

You can also use the same trick to have {smtp,nt}.dynamic and so on point
to somewhere appropriate depending on where you are.

So basically I guess I'm looking for tips. Has anyone done anything about
getting laptops to just work no matter where they're plugged in? Is there
anything that I just haven't thought of that makes this all easy and fun?
Should I just give up on the whole idea of not having to type anything to 
get networking working anywhere? Do I have any hope of getting UQ to move 
their proxy just to suit me, or is there a better way of telling netscape 
where its proxies are? 

Cheers,
aj, who doesn't think he'll try the full-justification-by-careful-word-choice
    trick anymore.

-- 
Anthony Towns <aj at humbug.org.au> <http://azure.humbug.org.au/~aj/>
I don't speak for anyone save myself. PGP encrypted mail preferred.

``Like the ski resort of girls looking for husbands and husbands looking
  for girls, the situation is not as symmetrical as it might seem.''
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