Start at Part 1

Configuring DHCPD

Reference: DHCPD(8) DHCPD.CONF(5)

I will start off by telling dhcp that I would like to advertise on both local network interfaces. On OpenBSD this information is kept in /etc/dhcpd.interfaces. The syntax is very simple, you merely state which interfaces you want, whether space-separated on the same line or just give each their own line in the file (like I did). Here’s my /etc/dhcpd.interfaces:

xl0
rum0

Now, lets set configure /etc/dhcpd.conf. As I stated in Part 1 I’ll be supporting two separate subnets, which I’ll create like this:

shared-network LOCAL-WIRELESS {
}
shared-network LOCAL-WIRED {
}

Nothing too crazy here, just two logical areas each labeled for ease of readability.

Since the local wireless section is pretty straight forward, I’ll do this one first. I’m going to start off with a global (subnet-wide) optional configuration, which is my domain name server list. I’d like to out that I’m using OpenDNS in this example, and openly invite you to do the same. So to make this configuration I’ll add the following line to the local wireless subnet area:

option domain-name-servers 208.67.222.222, 208.67.220.220;

Next I want everyone in the subnet to know which address to use for a gateway, so I’ll provide that configuration, seen here:

option routers 192.168.1.1;

Next is to set up the subnet which, as describe previously, is 192.168.0.1/24 and configured as follows:

subnet 192.168.1.0 netmask 255.255.255.0 {
range 192.168.1.32 192.168.1.127;
}

Here I’ve provided the range of offered IPs to be 192.168.1.32 up to and including 192.168.1.127, as well as provided gateway information to be given with the DHCP advertisements.

So now this whole subnet configuration will look like this:

shared-network LOCAL-WIRELESS {
option domain-name-servers 208.67.222.222, 208.67.220.220;
option routers 192.168.1.1;

 subnet 192.168.1.0 netmask 255.255.255.0 {
range 192.168.1.32 192.168.1.127;
}
}

Now lets set up to local wired subnet. For the most part it’s going to be the same. Which appears like this:

shared-network LOCAL-WIRED {
option domain-name-servers 208.67.222.222, 208.67.220.220;

option routers 192.168.0.1;

 subnet 192.168.0.0 netmask 255.255.255.0 {
range 192.168.0.2 192.168.0.127;
}
}

However, on this subnet I have two systems in which I’ll static map IPs to based on their MAC address, my xbox 360 and my opensolaris file server. So in this subnet setting, I’m creating a “group” and filling it in with the two hsots:

group {
host vault {
hardware ethernet 00:1a:92:e2:32:e1;
fixed-address 192.168.0.2;
}
host xbox {
hardware ethernet 00:12:5a:b6:92:1b;
fixed-address 192.168.0.3;
}
}

To start dhcpd, just run sudo dhcpd and you’re be all set. Lastly, to make this reboot safe we just need to edit /etc/rc.conf and set the dhcpd_flags to “” like this:

/etc/rc.conf:dhcpd_flags=""             # for normal use: ""

shared-network LOCAL-WIRELESS {
    option domain-name-servers 208.67.222.222, 208.67.220.220;
    option routers 192.168.1.1;
    subnet 192.168.1.0 netmask 255.255.255.0 {
        range 192.168.1.32 192.168.1.127;
    }
}

shared-network LOCAL-WIRED {
    option domain-name-servers 208.67.222.222, 208.67.220.220;
    option routers 192.168.0.1;

    subnet 192.168.0.0 netmask 255.255.255.0 {
        range 192.168.0.2 192.168.0.127;
    }
    group {
        host vault {
        hardware ethernet 00:1a:92:e2:32:e1;
        fixed-address 192.168.0.2;
    }
    host xbox {
        hardware ethernet 00:12:5a:b6:92:1b;
        fixed-address 192.168.0.3;
    }
}
}

Continue to Step 4.

Categories: Projects