ifflags -- network InterFace FLAGS hacking
can get / set flags and try to explain their meanings
work only on OpenBSD for the moment
send you patchs !

ifflags without argument : display help

ifflags interface_name : display interface status

ifflags interface_name flags : set interface with the given flags

How are flags are in the memory ?
Basically it's a bunch of bits that are either 0 or 1
for an easier (ie more compact reading) they are showed in hexa.