Generate random numbers on ipxe shell??

[mcb30]

(2014-01-16 07:40)oblivionv Wrote:  It is very unlikely that 2 clients assume the same address with randomization if we were to use a class B address for example.

Not as unlikely as you may think: http://en.wikipedia.org/wiki/Birthday_problem.

Quote:I agree that conflicting configurations from the DHCP server is not a sane option. But our environment is being used for testing with people setting up DHCP servers on cisco routers etc for academic purpose (by design). We faced a similar kind of issue with winpe wpeinit. But i was able to counter this with a batch script.

If you really need to hack around this problem rather than solve it, then you could try any of the following:

- use the "dhcp" command only to obtain an IP address, ignore any boot configuration, and "chain" from a hardcoded URI

- retry "dhcp" in a scripted loop until you get a configuration you are prepared to accept (e.g. using "isset" to check that you have a boot filename, or "iseq" to check that your default gateway is set to a specific IP address, etc.)

- use the undocumented (and not guaranteed to remain stable) "ipxe.priority" DHCP option to cause iPXE to prefer a specific DHCP server.

Michael