How to config DHCP for multiple subnet

applebees · 06-21-2010, 10:42 AM

Hello,

I have a network with multiple subnets from 10.12.056.0 to 10.12.060.0 using net-mask 255.255.248.0 and one gateway 10.12.056.1. I want to setup a dhcp server and wonder how should I config it? All the hosts in the network using the same net-mask and gateway.

Thanks,

deadeyes · 06-22-2010, 03:11 AM

You say they have different subnets right?
Then I wonder how this will work using the same gateway for each network.

Do you want to assign specific IPs to specific machines? Is each network on a different interface?

daveginorge · 06-23-2010, 05:14 AM

Here's my DHCP conf

Code:

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

option domain-name "domain.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 time-servers 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 time-servers 192.168.1.1;
	option domain-name-servers 192.168.1.1;
	range 192.168.1.130 192.168.1.149;
}

subnet 192.168.2.0 netmask 255.255.255.0 {
	option broadcast-address 192.168.2.255;
	option subnet-mask 255.255.255.0;
	option routers 192.168.2.1;
	option time-servers 192.168.2.1;
	option domain-name-servers 192.168.2.1;
	range 192.168.2.130 192.168.2.149;
}

subnet 192.168.3.0 netmask 255.255.255.0 {
	option broadcast-address 192.168.3.255;
	option subnet-mask 255.255.255.0;
	option routers 192.168.3.1;
	option time-servers 192.168.3.1;
	option domain-name-servers 192.168.3.1;
	range 192.168.3.130 192.168.3.149;
}

subnet 192.168.122.0 netmask 255.255.255.0 {
	option broadcast-address 192.168.122.255;
	option subnet-mask 255.255.255.0;
	option routers 192.168.122.1;
	option time-servers 192.168.122.1;
	option domain-name-servers 192.168.122.1;
	range 192.168.122.130 192.168.122.149;
}

Hope this helps

applebees · 06-28-2010, 10:17 AM

Quote:

Originally Posted by deadeyes

You say they have different subnets right?
Then I wonder how this will work using the same gateway for each network.

Do you want to assign specific IPs to specific machines? Is each network on a different interface?

Thanks for reply. Since it's a supernet uses netmask 255.255.248.0, it works.
The Dhcp server runs correctly with subnet 10.12.056.x, but not for other subnet although i put default gateway in all dhcpd.conf blogs. Any suggestion?

Thanks,

volga629 · 06-29-2010, 08:11 PM

Hi,
I would say you need use share network configuration for DHCP like this example

Quote:

shared-network name {
option domain-name "test.xxxxx";
option domain-name-servers ns1.xxxxxxxx, ns2.xxxxxxx;
option routers 192.168.1.254;
more parameters for EXAMPLE shared-network
subnet 192.168.1.0 netmask 255.255.255.0 {
parameters for subnet
range 192.168.1.1 192.168.1.31;
}
subnet 192.168.1.32 netmask 255.255.255.0 {
parameters for subnet
range 192.168.1.33 192.168.1.63;
}
}

and here the fixed IP another word DHCP reservation

Quote:

host name {
option host-name "name.xxxxxxx";
hardware ethernet 00:A0:78:8E:9E:AA;
fixed-address 192.168.1.4;
}

and last one is ip range declaration just single subnet

Quote:

default-lease-time 600;
max-lease-time 7200;
option subnet-mask 255.255.255.0;
option broadcast-address 192.168.1.255;
option routers 192.168.1.254;
option domain-name-servers 192.168.1.1, 192.168.1.2;
option domain-name "example.com";

subnet 192.168.1.0 netmask 255.255.255.0 {
range 192.168.1.10 192.168.1.100;
}

and here part of my dhcpd.conf about share networks

Quote:

ddns-update-style none;
deny bootp;
option wpad code 252 = text;

shared-network name {
interface name;
server-identifier xxxxxxxxxx; <-----default gateway
subnet xxxxxxxx netmask xxxxxxxx {

pool {
deny dynamic bootp clients;
default-lease-time 288000;
max-lease-time 576000;

option subnet-mask xxxxxxxxx;
option routers xxxxxxxxx;
option wpad "http://xxxxxxxxx/proxy.pac";
option domain-name-servers xxxxxxxxxxx, xxxxxxxxxxxx;
range xxxxxxxxx xxxxxxxxxxxxx;
}
}
}

Enjoy