This article describes the steps required to configure 802.1X client and server using EAP-TLS both client and server side in FreeBSD.

Background

I recently bought a new switch of ebay capable of 802.1X PNAC (Port based Network Access Control). I wanted to have this set up for a long time, but it wasn’t unil now I had a switch thats actually supported it. This article describes how I got it up and running.

Certificates

Since I already have EAP-TLS set up for my wifi (authentication using X.509 client certificates) I will also use EAP-TLS for wired access. So I configured a private CA in order to issue both server certificates for the radius server and also client certificates for all clients that will use my network.  I have a more general post about how set up the CA here.

Radius server (Authentication server)

You will need to configure a Radius server to handle the authentication requests. I already have EAP-TLS configured using hostpad and its internal radius server for my wifi. But that server is very limited, so I decided to give FreeRADIUS a go. This also means that my wifi clients will be authenticated using the FreeRADIUS server from now on.

I understand that FreeRADIUS is very flexible and “easy” to customize, but I really think that the configuration is very hard do grasp. It would be virtually impossible to configure it without some guide to follow. The two big problems are that the configuration is split up into MANY files and that all the documentation is inside the config files, which makes them really hard to read. Luckily I found this guide online that did exactly what I wanted. So please have a look at that guide under “Configuration” to see how I configured FreeRADIUS. Its basically just a few minor changes in four files.

The switch (Authenticator)

This article will not cover the switch configuration needed for this setup. The configuration you will have to do is very depended on what brand of switch you have and what software it is running.  I have a Juniper EX2200-C and there is good online documentation on how to set up 802.1X.

• Configure what radius server to use
• Configure individual ports

The Supplicant (802.1X client)

In 802.1X the client is called the supplicant. To authenticate against the radius server you will basically need a small supplicant software installed on the client that will handle the authentication. This is done using EAPOL-packages that are sent out on the network and then handled by the switch (The Authenticator). The switch then talks to the raidus server (The Authentication server) to verify the client.

In Linux and FreeBSD the most commonly used supplicant software is called wpa_supplicant. Most of you who know of wpa_supplicant have used it for wifi authentication in differents forms. It can handle alot of different security types like WPA2 Enterprise, WPA2 or even WEP. But it can also work with wired network authentication. The configuration is actually very straight forward and similar to the wifi configs.

network={
    key_mgmt=IEEE8021X
    eap=TLS
    identity="identity"
    ca_cert="/etc/ssl/chain.pem"
    client_cert="/etc/ssl/client.cert.pem"
    private_key="/etc/ssl/client.key"
    private_key_passwd="passw0rd"
}

This is all you will need to have wpa_supplicant authenticate using client certificates over ethernet.

To have the wpa_supplicant automatically started when you FreeBSD machine boots you can just add the WPA keyword to your interface declaration in /etc/rc.conf like this:

ifconfig_ue0="DHCP WPA"