How can I configure a DHCP server to assign addresses based on the OS that is running Solved maybe!

[Marc Chamberlin]

Hello -  I am going to pick up on a thread that I started last summer so 
as to give anyone who wants the context an opportunity to review and 
refresh themselves on the issues I am facing. Basically, I am trying to 
support dual and triple boot laptops with multiple OS's and multiple 
network interface capabilities (wireless v.s. wired), and I need to be 
able to assign these laptops a fixed IP address that is based on the OS 
that is currently running on them, regardless of what network interface 
is being used by the laptop. (the purpose behind this is so that our 
backup server can identify how to back up a laptop and reach that laptop 
via a known IP address) After a lot of discussion on this mail list, we 
reached a possible working solution and I will recap it (reshow what I 
summarized previously) below to show how the dhcpd.conf file was 
configured to manage one of these laptops (mine).

OK now for the problem, which was an unforeseen wrinkle, but users being 
users will discover em, and of course complain... If a user switches the 
network interface from one to another, while remaining with the same OS, 
then the dhcpd server will refuse to assign (actually reassign) the 
appropriate IP address to that laptop. (This happens a lot when a user 
takes his/her laptop to another building, out of range of our wireless 
AP) Since the dhcpd server thinks that the IP address for that laptop as 
already been assigned, to the wireless interface, and the user is now 
trying reboot and get an IP address assign via the wired interface, 
(which we want to be the SAME IP address) the dhcpd server fails to 
reassign the IP address until it's old lease expires.

So, anyone got any ideas on how to solve this new wrinkle? Thanks in 
advance for any and all offers of help, much appreciated?

      Marc Chamberlin...


---
>
> class "marcslaptop_Vista_Class" {
>    match if ((substring(option vendor-class-identifier, 0, 4) = 
> "MSFT") and
>             ((ucase(binary-to-ascii(16, 8, ":", substring (hardware, 
> 1, 6))) = ucase("0:1a:73:55:7d:f")) or
>              (ucase(binary-to-ascii(16, 8, ":", substring (hardware, 
> 1, 6))) = ucase("0:16:36:c2:65:a4"))));
>    log (info, "marcslaptop_Vista_Class matched");
> }
>
> class "marcslaptop_Linux_Class" {
>    match if ((substring(option dhcp-client-identifier,1,11) = 
> "marcslaptopLinux") and
>             ((ucase(binary-to-ascii(16, 8, ":", substring (hardware, 
> 1, 6))) = ucase("0:1a:73:55:7d:f")) or
>              (ucase(binary-to-ascii(16, 8, ":", substring (hardware, 
> 1, 6))) = ucase("0:16:36:c2:65:a4"))));
>    log (info, "marcslaptop_Linux_Class matched");
> }
>
> subnet 192.168.2.0 netmask 255.255.255.0 {
>   default-lease-time 14400;
>   max-lease-time 172800;
>   pool {allow members of "marcslaptop_Linux_Class"; range  192.168.2.10;}
>   pool {allow members of "marcslaptop_Vista_Class"; range  192.168.2.15;}
>   pool {
>         deny members of "marcslaptop_Linux_Class";
>         deny members of "marcslaptop_Vista_Class";
>         deny known-clients;
>         allow all clients;
>         range 192.168.2.101 192.168.2.199;}
> }
>