[TriLUG] dhcrelay troubles

[Aaron S. Joyner]

I'm not sure what dhcpd server Mandrake 9.2 comes with, but I would make 
a rough guess that it's ISC-DHCPd, although given the nature of your 
question perhaps not.  With ISC-DHCPd you need simply to assign two 
appropriate IP addresses to the ethernet devices (ala 192.168.0.x and 
192.168.3.x), and then define two different subnet declarations, 
something as such:

subnet 192.168.0.0 netmask 255.255.255.0 {
  range 192.168.0.100 192.168.0.250;
  default-lease-time 2592000;
  option subnet-mask 255.255.255.0;
  option broadcast-address 192.168.0.255;
  option routers 192.168.0.1;
  option domain-name-servers 192.168.0.1, 10.0.6.1;
  option domain-name "example.com";
  option netbios-name-servers 192.168.0.1, 10.0.6.1, 10.0.2.1;
}

subnet 192.168.3.0 netmask 255.255.255.0 {
  range 192.168.3.100 192.168.3.250;
  default-lease-time 2592000;
  option subnet-mask 255.255.255.0;
  option broadcast-address 192.168.3.255;
  option routers 192.168.3.1;
  option domain-name-servers 192.168.3.1, 10.0.6.1;
  option domain-name "wireless.example.com";
  option netbios-name-servers 192.168.3.1, 10.0.6.1, 10.0.2.1;
}

The appropriate addresses will then be served for the appropriate 
adapters, and dhcrelay need not be involved.

Hope that helps!
Aaron Joyner


Michael Hrivnak wrote:

>Here's the scenario:
>
>I use a Mandrake 9.2 box as a router:
>
>eth0: roadrunner
>eth1: wired lan
>eth2: crossover cable to a Linksys WAP11
>
>I want my dhcp server to be able to discriminate requests based on adapter 
>origin.  Thus, anything through eth1 will get a 192.168.1. address, and 
>anything through eth2 will get a 192.168.3. address.  In order to do this, I 
>run dhcrelay.  Here's the theory, based on some VPN howtos:
>
>Run dhcpd on eth1 and lo
>run dhcrelay listening on eth2 and lo
>
>So, we get this:
>
>dhcrelay -a -i eth2 -i lo 127.0.0.1
>
>The problem is that my WAP requests an IP address about three times a second 
>continuously.  If I accept this fact, it works.  My laptop connects 
>wirelessly and gets a 192.168.3. address.  The WAP keeps chugging away 
>though.  Somehow it's stuck in a loop that my laptop isn't.  What gives?
>
>I can start dhcrelay, and everything is quiet.  Request an IP from my laptop, 
>and it works great.  Only then will the WAP chime in, requesting an IP 
>address about 3-4 times a second.
>
>Any advice is appreciated!  Let me know if you want more details.
>
>Michael
>
>  
>