Home Wireless Router: FreeBSD 8

February 10th, 2010 By randy Categories: @Home

Perhaps a future post will demonstrate the use of FreeBSD for wireless AP’s in a commercial environment with roaming. This post will demonstrate a basic home router setup.

Hardware:

  • My wireless card (ath0) is equipped with the Atheros chipset.
  • Ethernet Nic (re0) is connected to a cable modem.
  • Ethernet Nic (em0) is connected to a switch for wired internet access.

Network:

  • Internal NAT: 10.0.0.0/24
  • We’ll bridge (bridge0) em0 and ath0′s wlan device (wlan0).
  • ISC-DHCP31 will respond to DHCP requests.
  • Packet Filter (PF) will do our routing.

You will need to know what to replace with your own configuration (not much).

Step 1: Install & Configure ISC-DHCP31 Server

  1. `cd /usr/ports/net/isc-dhcp31-server`
  2. `make && make install`
  3. Add dhcpd_enable=”YES” to your /etc/rc.conf file
  4. My /usr/local/etc/dhcp.conf looks like this (be sure to change the domain-name and any other custom settings):
subnet 10.0.0.0 netmask 255.255.255.0 {
  range 10.0.0.2 10.0.0.254;
  option domain-name-servers 4.2.2.1;
  option domain-name "CANAAN";
  option routers 10.0.0.1;
  option broadcast-address 10.0.0.255;
  default-lease-time 600;
  max-lease-time 7200;
}

Step 2: Configure Network Settings

  1. Add the following to /etc/rc.conf
pf_enable="YES"
pf_rules="/etc/pf.conf"
gateway_enable="YES"
wlans_ath0="wlan0"
create_args_wlan0="wlanmode ap"
ifconfig_re0="dhcp"   #remember this is my cable modem, it gets an IP address via DHCP
cloned_interfaces="bridge0"
ifconfig_bridge0="addm wlan0 addm em0"
ipv4_addrs_bridge0="10.0.0.1/24"
ifconfig_em0="up"
ifconfig_wlan0="ssid chicken up"
hostname="CANAAN" #You'll want to change this.

Step 3: Configure Packet Filter

  1. Add the following to /etc/pf.conf
nat on re0 from 10.0.0.0/24 to any -> (re0)

REMEMBER: re0 is the ethernet device connected to my cable modem. Your setup WILL be different. Want to learn more about that Packet Filter rule? Here is an EXCELLENT tutorial: http://www.openbsd.org/faq/pf/nat.html

Done! Who thought it could be so simple?

You can either restart your computer or:

  1. `/etc/rc.d/netif restart`
  2. `sysctl net.inet.ip.forwarding=1`
  3. `/etc/rc.d/pf start`
  4. `/usr/local/etc/rc.d/isc-dhcpd start`
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