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Old 02-28-2007, 03:53 AM   #1
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Unhappy Option user-class on DHCP client won't work

I have a win2003 dhcp server which validates both MAC addresses and requires the clients to provide a pre-defined user-class (eg 0x103dff8). When clients do not provide the user-class, they do not get a gateway but only an IP and netmask. This works perfectly with Windows clients but I can't seem to be able to get Linux clients to work. My clients are Fedora 5 or RedHat 9. The file I have been trying to manipulate is the /etc/dhclient.conf. Any guidance with this will be much appreciated. I'm fairly new to the Linux world.
Old 03-01-2007, 03:30 AM   #2
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hi, welcome to LQ!!!
Originally Posted by Khanye
I can't seem to be able to get Linux clients to work.
could you please elaborate on this a little bit??
Old 03-01-2007, 06:54 AM   #3
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The DHCP server checks the client MAC address and issues an IP address and an s/mask (but not the defaulty g/way).

I think usually people would just let the DHCP server use the MAC address to determine the client's identity and issue all the addresses. I am trying to get both the MAC address and an ID number which I will declare (the server will look for this ID) validated before a gateway is given by the server.

Trying to implement it in Linux using this:, as a guide. Where in the /etc/dhclient.conf do I place the classid? Do I need to have anything else in the file? Is it the correct file to use to tell the server the client's class ID?

As I say, the process is working well in Windows. I just issue the command IPCONFIG /setclassid "Local Area Connection" the-a-team as guided by;en-us;235272
Old 08-25-2016, 01:37 AM   #4
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I'm discovering the Slackware distro, and I'm stuck with the same issue : in our DHCP setup, all our DHCP clients (windows or Linux) are configured to send user-class option to the DHCP servers. Requests with no classID are rejected.

Under Debian-like distros, we modify
by adding
send user-class "blahblahblah";

I'm trying to use Slax (derived from Slackware), and the only relevant file I found is /etc/dhcpd.conf .
In this file, I tried to add :
userclass blahblahblah
option userclass blahblahblah
user-class blahblahblah
option user-class blahblahblah
userclass "blahblahblah"
option userclass "blahblahblah"
user-class "blahblahblah"
option user-class "blahblahblah"

with reboots between each try.

To no avail.

Using a static network configuration is working well, but it is not what's needed.

Is this /etc/dhcpd.conf the right place to setup the DHCP *CLIENT*?
How comes this parameter does not seem to be passed onto the DHCP server?

Thank you.



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