Steffen Dettmer wrote: > I configured several interfaces using ifupdown using DHCP by stanzas like: > > auto eth2 > iface eth2 inet dhcp Your indention is terrible! Don't indent the iface line. Indent lines _after_ the iface line that modify the iface. > When booting and one of the DHCP interfaces has no cable attached, > booting is delayed about around 60 seconds (seems to be value of > dhclient.conf:timeout). Why isn't your DHCP server responding? Your dhcp server should respond quickly and provide an IP address. If it is not then look there to solve the problem. Debug your dhcp problems first. > I think I have to pass the option "-nw" to dhclient, but how do I do > that correctly? If you want dhclient not to wait then change the "auto" to "allow-hotplug". Using "auto" means bring the interface up at system boot time. It runs the /etc/init.d/* scripts. This is a synchronous operation. "allow-hotplug" means bring the interface up when the interface is detected. That is the new dynamic event driven way and runs asynchronously. The "auto" and "allow-hotplug" are documented here: http://www.debian.org/doc/manuals/debian-reference/ch05.en.html#_the_basic_syntax_of_etc_network_interfaces > I noticed that DHCP leases are kept as long as the lease is valid when > moving from one LAN to another, not sure if this behavior is correct. It is required. It is possible for clients to actively release the lease. But if a client crashes then the dhcp server never gets an indication and therefore must keep the lease active for the full time to live. > I considered ifplugd which solves both issues, but then all static > addresses of the interface are missing as long as no cable is plugged > (which might usually be expected on Desktops / Laptops, but might not > be desired on other devices, because it prevents from binding sockets > to specific IP addresses). If an application needs to bind to a specific address then IMNHO it should detect when this interface becomes active and track the events itself. Nothing else makes sense. IMNHO. Instead I would go ahead and use a wildcard listen address. And use iptables to block access to the undesired addresses. A completely different strategy. > How to configure DHCP correctly without causing boot delays? Use "allow-hotplug". Bob
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