I have a similar set up here, well, not here, at home. It's slightly
complex. I use DHCP to assign a fixed IP address no matter what
interface I'm using. If I want to switch from one interface to another
manually I do "ifdown ethN; ifup ethM" (N and M being 0 and 1, but not
necessarily in that order). Mostly I don't need to do that since I
either have wireless or wired available but not both. Since I keep the
same IP address, I can even maintain a TCP connection while I'm swapping
hardware -- it looks odd, but it works. Well, it did the one time I've
actually done that. It's great there was a file transfer pootling
along at, oh, perhaps as much as a megabyte a second and then it
suddenly shot up to 9 meg a second when I plugged the wired connection in.
In the office, I have a different IP address and that's hardwired to the
same two MAC addresses. There's a slight problem in moving from home
to work and vice versa -- applications tend to read /etc/resolv.conf
when they start up and use that to decide which name server to talk
to. Unfortunately, the name server at home isn't reachable from work
and the name server at work doesn't do recursive queries from outside
(and doesn't know about the private network at home). The upshot of
that is that I have to restart some applications (e.g. mozilla,
rhn-applet-gui, nfs server) when I go from work to home or back again,
and sometimes there's enough confusion that it's easier to reboot.
This is one of the primary things that makes me think I want to stay with my Mac OS X laptop for at least a while longer. If you have to roam between several different networks, many of which are static only, no DHCP, Linux (and Windows, for that matter) can be a real PITA. Mac OS X still has the best damned setup for a laptop in these kinds of situations. You set up a location profile, which contains what interface to use, what gateway to use, what DNS servers to use, DHCP or static, etc., and it is all shift on the fly from either the control panel or the Location sub-menu of the Apple menu. Apple's the only one that's got it right, so far. I sure would like to see such a thing under Linux...
--
Jarod C. Wilson, RHCE
<jcw@xxxxxxxxxxxx>
"A wise man once said nothing at all."
