Line 25 of ifup-post (initscripts-5.00-1) contains a
check that prevents the script from setting the hostname
for interfaces that have not been activated at boot time ("$2" = "boot").
This is inconvenient for PCMCIA adapters where the interface is
never activated at boot time.
This is intentional; for PCMCIA adapters and other things that
could be changed often on the computer, we don't want
to set a hostname; changing the hostname at random points
during runtime can cause application
failures (X being the notable example.)