Yes, THAT's it.
You use the ARP REQUESTS of the double to detect that it's using your
IP. That's the "runtime" check.
As I was the original one to suggest doing the gratuitous ARP in the
first place, and people have convinced me that not ifconfiging the
interface is NOT a good idea, I've done some more thinking:
The "don't ifconfig it" is good for when someone is manually playing
with ifconfig, and making a typo. The "ifconfig anyway" approach is
good for servers which happen to boot during a "hostile takeover".
How about printing a message, and waiting 10 seconds before
continueing to ifconfig the interface? That will annoy the
slippery-finger-sysadmin to the point of reading the message and
pressing control-C to prevent the mixup.
Note that if you happen to have an important old server sitting
somewhere and you are test-driving the new machine, the new machine is
likely to be faster and get registered in other people's arp caches
for quite a while even if the "bad" situation lasts just a few
seconds.
Roger.
-- ** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 ** *-- BitWizard writes Linux device drivers for any device you may have! --* ------ Microsoft SELLS you Windows, Linux GIVES you the whole house ------
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