On Thu, Jul 17, 2008 at 06:53:25PM -0700, Freddy Freeloader wrote: ... > > These troubleshooting suggestions really don't help explain to me why > dhclient would override the settings in /etc/network/interfaces for one > NIC and not the other though. And why would it override manual > settings? Isn't there some process watching the settings in > /etc/network/interfaces to stop just such a thing from happening, or > doesn't the driver and device itself record its state so that dhclient > wouldn't even attempt this unless there is some type of user override, > i.e. ifdown/ifup, /etc/init.d/networking restart, etc... ? so far as I know, interfaces is only read once, when it's needed, at the time the interface is upped. Once it's up, that file's not read. You can test this by upping an interface, commenting it out of interfaces and then trying to down the interface (ifdown). It will fail because it can't find the interface in the file. At least that's how I remember it. > > There's something going on that I really don't understand here, and just > troubleshooting it at the level shown here doesn't seem to me that it > will answer my base questions. Can anyone point me to documentation on > how this works, because I must be missing something. > > Why wouldn't restarting networking not have killed dhclient after > /etc/network/interfaces was read, the NIC's configured, and all NIC's > were configured with a static IP address? dhclient doesn't care about /etc/network/interfaces at all. It just tries to get dhcp lease over the specified interfaces. Why only the one interface? because something is specifying that interface to dhclient. WHy doesn't the process get killed? because the rest of the networking system doesn't know about it. When you start networking, or do an ifup, those scripts keep track of the dhclient that it starts by pid. If dhclient is started by some other process, those scripts don't know about it. At least, again, that's how I understand it. That comes from just using them a lot, playing with it to see what it does. The canonical answer is to be found in the code. best A
Attachment:
signature.asc
Description: Digital signature