Developers guide

Chapter 5

Configuration 24

By default no DHCP Server should be running on that interface where you are sending the requests. This

is by design otherwise PacketFence would reply to the DHCP requests which would be a bad thing.

Obtain a copy of the DHCP traffic

Get a copy of all the DHCP Traffic to a dedicated physical interface in the PacketFence server and

run pfdhcplistener on that interface. It will involve configuring your switch properly to perform port

mirroring (aka network span) and adding in PacketFence the proper interface statement at the operating

system level and in pf.conf.

/etc/sysconfig/network-scripts/ifcfg-eth2:

DEVICE=eth2

ONBOOT=yes

BOOTPROTO=none

Add to pf.conf: (IPs are not important they are there only so that PacketFence will start)

[interface eth2]

mask=255.255.255.0

type=dhcp-listener

gateway=192.168.1.5

ip=192.168.1.1

Restart PacketFence and you should be good to go.

Interface in every VLAN

Because DHCP traffic is broadcast traffic, an alternative for small networks with few local VLANs is to

put a VLAN interface for every VLAN on the PacketFence server and have a pfdhcplistener listen on

that VLAN interface.

On the network side you need to make sure that the VLAN truly reaches all the way from your client to

your DHCP infrastructure up to the PacketFence server.

On the PacketFence side, first you need an operating system VLAN interface like the one below. Stored

in /etc/sysconfig/network-scripts/ifcfg-eth0.1010:

# Engineering VLAN

DEVICE=eth0.1010

ONBOOT=yes

BOOTPROTO=static

IPADDR=10.0.101.4

NETMASK=255.255.255.0

VLAN=yes

Then you need to specify in pf.conf that you are interested in that VLAN’s DHCP by setting type to

dhcp-listener.