DHCP

daveginorge · 05-21-2009, 11:58 AM

Hi All
I have been reading the post here for a long time and I still cannot get my brain around how to do this.

Senario. CentOS 5.3 box 2 NICS supplying 2 different LANS which should have 2 different IP ranges. Lan1 10.70.70.0 Lan2 192.168.1.0

Right now my DHCP server supplies Lan1 without problems and has done for years, now I wish to introduce Lan2 to the server and reconfigure the DHCPD.conf to allow the second range of addresses.

This code with subnet "Lan1" has been working for years

default-lease-time 600;
max-lease-time 7200;
option subnet-mask 255.255.255.0;
option broadcast-address 10.70.70.255;
option routers 10.70.70.1;
option domain-name-servers 10.70.70.1;
option domain-name "mydomain.no";

So now I would have the 2 subnets.

#Lan1 eth0
subnet 10.70.70.0 netmask 255.255.255.0 {
range 10.70.70.130 10.70.70.149;
}

#Lan2 eth3
subnet 192.168.1.0 netmask 255.255.255.0 {
range 192.168.1.130 192.168.1.149;
}

How do I bind the NICS eth0 and eth3 to their respective subnet. I can handle the routing in the iptables no problem, I just cannot work this out.

Thanks in advance.

acid_kewpie · 05-21-2009, 12:31 PM

You don't need to bind them, it knows what addresses it is listening on, but you'll need a different default gateway for the new subnet.

daveginorge · 05-21-2009, 01:12 PM

Let me see if I get this.
What your saying is that if I create this as a script, the system will automatically configure the 1 subnet on each of the NIC's

Code:

default-lease-time 600;
max-lease-time 7200;
option subnet-mask 255.255.255.0;
option broadcast-address 10.70.70.255;
option routers 10.70.70.1, 192.168.1.1;
option domain-name-servers 10.70.70.1;
option domain-name "mydomain.no";

#Lan1 eth0
subnet 10.70.70.0 netmask 255.255.255.0 {
range 10.70.70.130 10.70.70.149;
}

#Lan2 eth3
subnet 192.168.1.0 netmask 255.255.255.0 {
range 192.168.1.130 192.168.1.149;
}

I'm hoping it is that easy

daveginorge · 05-22-2009, 01:59 AM

Found the answer. Code posted for others in the future

Code:

default-lease-time 600;
max-lease-time 7200;

option domain-name "mydomain.no";


subnet 10.70.70.0 netmask 255.255.255.0 {
	option broadcast-address 10.70.70.255;
	option subnet-mask 255.255.255.0;
	option routers 10.70.70.1;
	option domain-name-servers 10.70.70.2, 10.70.70.1;
	range 10.70.70.130 10.70.70.149;
}

subnet 192.168.1.0 netmask 255.255.255.0 {
	option broadcast-address 192.168.1.255;
	option subnet-mask 255.255.255.0;
	option routers 192.168.1.1;
	option domain-name-servers 192.168.1.1;
	range 192.168.1.130 192.168.1.149;
}

ddns-update-style ad-hoc;