Bind ip with mac address

sunlinux · 08-07-2007, 04:33 AM

with DCHP server:

is it possible to bind mac address of dhcp clients with particular ip address, so if a user change ip, It does not work in lan.

culin · 08-07-2007, 06:35 AM

you can bind a particular IP address to a MAC address like this...
host ns {
next-server marvin.redhat.com;
hardware ethernet 00:14:22:58:1D:4F;
fixed-address 207.175.42.254;
}

in the /etc/dhcpd.conf file...

muha · 08-07-2007, 06:43 AM

@culin: is that restrictive? Like, if the client just chooses its own ip and uses that on the lan, that would not be blocked in any way, right?

sunlinux · 08-07-2007, 11:42 PM

agree with muha question...

MQMan · 08-08-2007, 11:13 AM

Are you asking about a user who puts in their own IP, instead of using DHCP. If so, then it will be a fixed IP, and DHCP won't be involved. DHCP will only hand out IPs to clients, who request one.

Or are you asking about a user who takes his machine off one network, using DHCP, and connects it to yours, where, initially, the client will try and renew the existing IP. In this case, DHCP should reject that request, and the client will then request a new IP, which will be the one specified in your DHCP configuration.

Cheers.

daveginorge · 08-10-2007, 01:23 AM

You would need to set up DHCP as "Culin" has stated in his previous post, this will always supply the same IP adress to a particular MAC address.

If the user changes the IP adress manually, you will need to block this on your Firewall using IP tables to allow only the DHCP adresses.

HTH