DHCP & known MAC addresses

Rodolfo J. Paiz rpaiz at simpaticus.com
Tue Mar 16 21:25:38 UTC 2004


At 10:09 3/16/2004, you wrote:
>Is there a way I can assign DHCP managed IP addresses to only computers
>with known MAC addresses?

deny                    unknown-clients;

>Currently, I'm giving out IP addresses to any DHCP request using:
>
>         subnet 123.456.789.0 netmask 255.255.255.0 {
>                 range 123.456.789.240 123.456.789.245;
>         }
>
>I only want to give out IP addresses to known computers without
>assigning specific IP addresses to specific MAC addresses.   Our pool of
>known computers is bigger than our pool of IP addresses, but all the
>computers will never be present at the same time.

Make the lease time short, something like an hour, with:

max-lease-time                          86400;
default-lease-time                      86400;

Now, try something like the following either after or maybe inside your 
"subnet" declaration:

group {
         use-host-decl-names             on;

         host adan { hardware ethernet       00:50:ba:5d:6f:2c; }
         host rodolfo { hardware ethernet       00:d0:59:b7:48:41; }
         }

This way you are defining the known hosts but *not* assigning fixed addresses.

The above should be a guide, to be completed by consulting the man page for 
dhcpd.conf. It is not a complete answer since I have not needed to do what 
you want so I have not tested this solution.

That being said, I do deny unknown clients and I do assign fixed IP 
addresses to hosts adan and rodolfo by adding "fixed-address" commands 
inside each "host" section. So I should be close, even if I'm not exactly 
right.


-- 
Rodolfo J. Paiz
rpaiz at simpaticus.com
http://www.simpaticus.com





More information about the redhat-list mailing list