Dhcpd two IP ranges via two nics

rvjaarsveld · 10-14-2004, 03:32 AM

Hi,

Im have a Fedora 2 Box with two (2) ethernet adapters
I want to configure DHCPD to distribute the 10.0.0.1 / 24 range via eth0
and distrubure 192.168.0.1 /24 range via eth1

Is this possible ?
The reason I want it set like this is I have 1 Linux box, that will act as a DHCP server for two networks as described above.

The one ethernet will be in a Vlan , the second ethernet will be in another vlan hense the configuration to distribute the two IP ranges

Can anyone please help ? is it at all possible ?

Thanks
Riaan

Frustin · 10-14-2004, 05:34 AM

oops i didnt read the post, yes, you can do that. i havent looked at how.

rvjaarsveld · 10-14-2004, 06:33 AM

That is all nice, I have been told numerous times its do-able, does anyone perhaps know how

Thanks guys

Frustin · 10-14-2004, 06:35 AM

i would like to quote you on your first edit: " is it at all possible ?", to which i answered yes.

rvjaarsveld · 10-14-2004, 06:51 AM

Cool, sorry for that. Its just becoming a frustration at the moment.
I cant kinda gather u wont be able to do it, because of the fact that your nics are on your network layour, and the fact that you cant run two instances of dhcpd.

anyone have got any input regarding this will be greatly appreciated

Frustin · 10-14-2004, 06:58 AM

gimmie a bit to think about it and do a bit of googling.

rvjaarsveld · 10-14-2004, 07:00 AM

thanks !

scowles · 10-14-2004, 07:21 AM

If I'm understanding your post correctly - just add two subnet declarations to dhcpd.conf, one for each interface/network. Something like the following should work, just edit to meet your requirements. Note: This is a copy/paste from my own dhcpd.conf

Code:

#################################################
# GLOBAL Options: Every DHCP enabled client
# will inherit the following options unless
# overiden within the subnet/host scopes.
# below
#################################################
authoritative;
option domain-name-servers 192.168.9.3, 192.168.8.2;
option domain-name "mydomain.com";
option netbios-name-servers 192.168.9.2;
option netbios-node-type 8;
 
# If some clown tries to request a rediculous lease
# time (like 365 days), set resonable values here.
min-lease-time 60;              # 1 Hour
default-lease-time 86400;       # 1 Day
max-lease-time 172800;          # 2 Days

subnet 192.168.8.0 netmask 255.255.255.0 {
 
    option subnet-mask 255.255.255.0;
    option broadcast-address 192.168.8.255;
    option routers 192.168.8.1;
}

subnet 192.168.9.0 netmask 255.255.255.0 {
 
    option subnet-mask 255.255.255.0;
    option broadcast-address 192.168.9.255;
    option routers 192.168.9.1;
}

rvjaarsveld · 10-14-2004, 07:41 AM

Thanks for the reply.

You are kinda answering my question although let me explain to you the actual problem

a) My eth1 issues IP range 192.168.0.1 /24
b) My eth0 issues IP range 10.0.0.0 /24

Now depending on where you come from (So in other words) which interface you request the information from you get the relevant IP

Now, in the ..../sysconfig/dhcpd I have allowed both ethernet's to listen for request

Now the problem comes in where you move a PC from a ethernet network to the other, the lease file remembers that it was a 192, now its a 10, and it confuses itself.

So the solution either is , to script the lease to clear every 1 hour, or to lease every 1 hour (but by doing this , you kinda miss the purpose of what you want to achieve)

Hope this helps

Another thing is you cant run two instances of dhcpd
I have tried starting it via script to use its own conf file and lease file, but you can only run one instance and it defaults back to the /etc/dhcpd.conf file

Spoken to alot of linux guys , they say im trying to be clever , but I'm more than sure, there must be a way

Thanks Guys

Riaan

scowles · 10-14-2004, 08:03 AM

Why can't you create a group/pool (see man dhcpd.conf) within the subnet declaration for your laptops. Then make the lease time for these laptops something like 5 minutes. Then the desktps PC's will inherit the global 1 day lease, your laptops 5 minutes.

rvjaarsveld · 10-14-2004, 08:29 AM

Hi Yip , That was an Option

I have it working!!!!!!!!!

Only thing u need to do is specify the two ranges as per your config, and them in /etc/sysconfig/dhcpd remove everything

so in essence , dont allow any ethernet to listen , otherwize it keeps the old config

Thanks for the help guys.

If anyone wants to do what I did, and Cant figure it out via these posts, please just reply to this post, and I will try my best to help you as well

Regards
Riaan