conditional sentences

Glenn Satchell Glenn.Satchell at
Mon Sep 18 13:59:40 UTC 2006

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>From: muzzol <muzzol at>
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>Subject: conditional sentences
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>i want to create a subnet only for windows users and another for linux.
>how i can identify operating system?
>is dhcp-eval the right direction?
This is from the dhcp-options manual page.

     option vendor-class-identifier string;

       This option is used by some DHCP clients to  identify  the
       vendor  type  and  possibly  the  configuration  of a DHCP
       client.  The information is a string of bytes  whose  con-
       tents  are specific to the vendor and are not specified in
       a standard.   To see what vendor class identifier  clients
       are  sending,  you  can  write  the following in your DHCP
       server configuration file:

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

       This will result in all entries in the DHCP  server  lease
       database   file   for   clients  that  sent  vendor-class-
       identifier options having a set statement that looks some-
       thing like this:

       set vendor-string = "SUNW.Ultra-5_10";

and you can use it like this. "MSFT 5.0" is returned by windows 2000
and XP.

class "windows" {
  match if option vendor-class-identifier = "MSFT 5.0";

You could do the same thing for linux, but there doesn't seem to be a
default value set, although you could set it on each client.

In appropriate pools either in the same or different subnets configure
an allow or deny for the particular classes.

  pool { # windows clients only
    range ...
    allow members of "windows";
  pool { # everything except windows clients
    range ...
    deny members of "windows";

Glenn Satchell       mailto:glenn.satchell at  |  Heard about
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