hostid gives identical values on all FC machines

[Aleksandar Milivojevic]

Matthew Saltzman wrote:
> But MAC address is not bad (though, of course, anything can be forged with
> more or less effort).  Solaris generates the hostid from the MAC address
> of the primary NIC.

If we are talking about Sparc machines, the above statement is not true. 
  Sparc has actual hostid stored in PROM chip.  Hostid is stored in 
bytes 1, c, d and e, while MAC address is stored in bytes 2-7 of this 
chip.  Byte 1 of hostid is machine type (don't touch it), and the 
remaining three bytes (also called serial number) you can set to preatty 
much anything you want.  Hostid command will simply read out those bytes 
form PROM chip and display them on the screen.  MAC address is sometimes 
set to be identical to hostid, but it can be different (not stored in 
same location on the chip).  You can also set it to preatty much 
anything you want (but some Sun boxes will complain if first three bytes 
are not set to 08:00:20).  Don't forget to recalculate and store new 
checksum into byte f, or you'll be in deep poop.

Luckily, there's port of Fedora Core for Sparc machines, which makes the 
above not totally off topic ;-)

-- 
Aleksandar Milivojevic <amilivojevic at pbl.ca>    Pollard Banknote Limited
Systems Administrator                           1499 Buffalo Place
Tel: (204) 474-2323 ext 276                     Winnipeg, MB  R3T 1L7