On Tue, 24 May 2005 09:47:31 +1200 Andrew Errington wrote: > Hi, > > Apologies in advance for vagueness, but I have a question about dhcp. I > have set up a system that is supposed to run unattended and automatically > configure at boot, but there was a problem for which I had a cheesy > workaround. My question concerns a) The problem, b) the workaround and c) > does Windows do this? > > Basically, as I understand it, if a Linux machine is configured as a DHCP > client, and the DHCP server is unavailable at boot time (for example, the > ethernet cable is not plugged in) then everything that loads up after that > point gets a broken network configuration (something to do with resolv.conf > I think).
More the fact I think that there is no network interface to bind to. *Some services will appear to start, but won't work properly * some services will start bound to lo only * some service won't startt at all. It all depends on your init scripts essentially. At a guess you will be using debian (I know your preferences LOL).I would develop a script that: 1. stops all services dependent on the network 2. restarts the network service 3. starts all services dependent on the network >Plugging the cable back in has no effect, and there is no soft > way of getting it configured again automagically because some software > caches the broken configuration and won't flush it. (I tried looking for a > Google reference, but can't find anything that describes this succinctly, > and I'm not sure even sure I am describing it very well). Anyway, the > solution is to reboot the machine and assume that fault goes away > eventually. To that end my system literally does that- if networking is > fundamentally broken at start-up, reboot. This is different from a network > *becoming* broken, where it is sufficient to retry. > > It was a while since I worked on this, and it's all a bit vague. It was > hard enough the first time round figuring out a good solution, and > rebooting actually was the best way. > > If someone understands this problem, could you please give me a reference, > to remind me why it is so fundamental. Also, is there a better solution > than rebooting? I cannot put defaults in for dhcp, since the machine could > move around so the defaults for one network make no sense for another. > > Andy -- Nick Rout
