"dhclient -1" considered harmful

[Philipp Kern]

netcfg in Ubuntu diverges from the one in Debian by using dhclient from isc-dhcp-client instead of udhcpc (well, except kfreebsd and hurd). dhclient is run with -1 to acquire a lease once and exit. With short lease times configured on the DHCP server (say, half an hour) and DHCP snooping enabled on switches, the installer will lose network connectivity once the lease expires. "-1" ensures that dhclient does not daemonize and hence it will not continuously renew the lease. I recall some differences in behavior with "-1", though, related to how it handles not getting a lease at all (I think it's forking into the background and continue trying instead of failing and exiting). So this would need some fixing, hopefully through configuration options. As the file is already written out, there should be full flexibility there.