How do you discover client's vendor-class-identifier option?

Glenn Satchell Glenn.Satchell at
Mon Sep 21 00:45:27 UTC 2009

>From: "Nathan C. Smith" <nathan.smith at>
>Is there a way to discover the vendor-class-identifier a client will transmit 
when it requests a lease?  Obviously I'm hoping there is a database somewhere.
>Failing that, is wireshark an option for finding it or is there a logging 
option I can turn on to discover it?
>Many thanks.

This is a bit after-the-fact, but is exactly what dhcpd will see.
Add this line to your dhcpd.conf:

set vendor-string = option vendor-class-identifier;

Then have a look at the lease for the particular client in
dhcpd.leases. It will contain an entry something like this:

% grep vendor-string /var/dhcp/dhcpd.leases | sort -u
  set vendor-string = "MSFT 5.0";
  set vendor-string = "PXEClient:Arch:00000:UNDI:002001";
  set vendor-string = "SUNW.i86pc";

Glenn Satchell   mailto:glenn.satchell at | Miss 9: What do you
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