DHCP options

Glenn Satchell Glenn.Satchell at uniq.com.au
Tue Sep 29 04:34:47 UTC 2009

>Date: Mon, 28 Sep 2009 13:43:29 -0500
>Subject: DHCP options
>From: DT DT <dt.techno99 at gmail.com>
>To: dhcp-users at lists.isc.org
>X-BeenThere: dhcp-users at lists.isc.org
> Hello,
> I request your help in case somebody knows about the time options for a DHCP
> server:
> At the company where i work we have implemented a NTP server, we have a
> large amount of ntp clients we want to sincronize (windows XP most of them).
> We are thinking of using DHCP options to try to send the NTP server address
> as well as the correct time zone (UTC-6 & UTC-7).
> We have tested on linux clients and they take the NTP server address but not
> time zome; windows clients seem to ignore these 2 settings the DHCP server
> sends them.
> These are the options we have implemented on the DHCP server to send NTP
> server settings and timezone:
> option pcode code 100 = text;
> option tcode code 101 = text;
>  ......
>  option ntp-servers;
>  option pcode "CST6CDT";
>  option tcode "America/Mexico_City";
>  option time-offset    -21600;
> I appreciate any advice you may have.
> Best Regards,
> Alma R.

Hi Alma

The dhcp-options man page lists all the DHCP options that the dhcp
server can set, but that does not mean every client will use all of

You will need to look up the documentation for your various clients.
There are only a few mandatory options that clients must implement.
There are a lot that are, well, optional.

Each client has an option that it sends listing the option fields that
it wants the dhcp server to supply. If the client does not request a
particular option then the dhcp server will not send it. Even if you
force the server to send an option, the client may not know how to
decode and use the value.

Glenn Satchell   mailto:glenn.satchell at uniq.com.au | Miss 9: What do you
Uniq Advances Pty Ltd       http://www.uniq.com.au | do at work Dad?
PO Box 70 Paddington NSW Australia 2021            | Miss 6: He just
tel:0409-458-580     fax:02-9380-6416              | types random stuff.

More information about the dhcp-users mailing list