Balint Marton wrote:
At boot time, get_random_bytes always returns the same
random data, as if there were a constant random seed.
packet with always the same transaction ID. (If you have
more than one computers, and they are booting at the
same time, then this is a big problem)
If many systems are booting at the same time, is seeding with the system
time really an appropriate solution? Shouldn't some system-specific
value also contribute to the randomization?
On Mon, 26 Jul 2004, Eble, Dan wrote:
If many systems are booting at the same time, is seeding with the system
time really an appropriate solution? Shouldn't some system-specific
value also contribute to the randomization?
Yes, i agree, it would be nicer, if we could also use some
system-specific stuff for the seeding, but i don't know if there is
such data during the initialization of the random module. For example,
we may use the MAC address of a network device, but unless i am mistaken
the initialization of such network devices take place after the random
dirver init.
By the way, i made a little test with 40 computers. They were totally
equvivalent by hardware, and all of them had a synchronized system
clock. I turned them on by Wake On LAN exactly at the same time. All of
them used the kernel level ip autoconfig, all of them got their right IP
address, and i didn't even find a line of DHCPNAK in the dhcpd logfile.
Conclusion: Although using some system-specific data and the clock would
be nicer, the system time alone also does the right thing dependably.
bye,
Cus
Hi,
In my previous email, i wrote about a 40 computer test.
Today, I repeated my test, and although every computer got the right IP
address, there were at least 7 lines of DHCPNAK in the dhcpd logfile.
So the system time alone is not as good as it looked like.
Cus