How can I configure a DHCP server to assign addresses based on the OS that is running Solved maybe!
Marc Chamberlin
marc at marcchamberlin.com
Sun Jan 16 18:10:19 UTC 2011
On 1/16/2011 4:27 AM, Glenn Satchell wrote:
> Perhaps forcing the client to release the IP when shutting down might
> work for you? I am not sure wha happens if you suspend, or just pickup
> the laptop and move it while running.
Thanks Glenn for the idea of running a script or configuring the DHCP
client on each laptop to release its lease when it shuts down. Deploying
this approach to each laptop is, as always, a bit of a headache, but
doable. As for those who simply suspend the laptop, or move it while
running, a reboot will fix the IP assignment and guess we will just have
to live with that. Not a perfect answer, but what is? LOL
It will sure beat the approach I have been taking, when I get a
complaint, which is to stop the dhcpd server, hand edit the leases
database file and remove the particular lease from it, then restart the
dhcpd server!
>
>
> A few other minor notes about your posted dhcpd.conf:
>
> This will never match, the substring is 11 chars long, but you're
> testing for equality with a 16 char string. Cut and paste error in the
> email perhaps? The 11 should be replaced by the length of the string,
> 16 in this example.
>
> substring(option dhcp-client-identifier,1,11) = "marcslaptopLinux"
Oops! More of a hasty edit/touch up error on my part, trying to make it
clear what I am doing. My laptop, under Linux, actually identifies
itself simply as "marcslaptop"
>
> And this might be a little pedantic, but you can re-write this:
>
> (ucase(binary-to-ascii(16, 8, ":", substring (hardware, 1, 6))) =
> ucase("0:1a:73:55:7d:f")
>
> in a much simpler form:
>
> ((substring (hardware, 1, 6)) = 0:1a:73:55:7d:f )
>
> Admittedly, with the processing capability of today's CPUs it probably
> won't make that much difference.
>
> You can directly compare with a hex digit string. See this section of
> the dhcp-eval man page:
>
> $ man dhcp-eval
> ...
> colon-separated hexadecimal list
>
> A list of hexadecimal octet values, separated by colons,
> may be specified as a data expression.
Awww.... Guess I missed this when I did the configuration! Always happy
to simplify my life! Thanks for the tip!
Marc...
>
> regards,
> -glenn
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