On Friday, Jun 6, John Haxby wrote: 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...
It's slightly tricky.
The first part is easy though -- neat allows you to have multiple profiles although I've not felt the near to try it just yet.
The second part is slightly harder -- the resolver library needs to check to see if /etc/resolv.conf has changed and if it has, it needs to re-load it.
The third part is the hard part because it affects applications. I can imaging some applications getting upset if a name that previously resolved doesn't any more. Things like bind are going to have a harder time since they bind to the IP address for each interface so that they can correctly reply to requests (what do you mean, you don't run bind on your laptop :-))
However, if the resolver library was fixed to spot a changing /etc/resolv.conf that would fix almost all the problems that I ever get ... I might tackle that one day when I'm feeling bored. I wonder how much it would affect overall performance? Probably not much.
jch
