Network access control on wired networks with IEEE 802.1X
Monitoring
In production use, you can monitor these activities by entering tail -f /var/log/radius/radius.log:
Info: Ready to process requests. Auth: Login OK: [uebelacker] (from client uebelhackers port 13 cli 00:19:e0:18:38:5c)
This output indicates that the owner of the certificate issued to uebelacker has logged in to switch port 13. Both Xsupplicant from the OpenSEA Alliance's [7] Open1X project [8] and the slightly better known wpa_supplicant [9] support this type of supplicant login. However, some distributions do not include these two supplicants. On Ubuntu 9.04, the Network Manager acts as a graphical front end for wpa_supplicant (see Figures 2 and 3).
![](/var/linux_magazin/storage/images/linux-magazine.com/issues/2009/108/ieee-802.1x/figure-2/421883-1-eng-US/Figure-2_large.png)
On the Client
The user needs to configure an 802.1X profile in /etc/xsupplicant/xsupplicant.conf (see Listing 6), which can be tested by calling the supplicant as follows:
xsupplicant -D wired -i eth0 -d 5 -f -c /etc/xsupplicant/xsupplicant.conf
Following 802.1X authentication and the unlocking of the network port, which the tool indicates by announcing Changing from AUTHENTICATING to AUTHENTICATED, the start script assigns either a static IP or uses DHCP in the normal way. If the Xsupplicant is run in the background using /etc/init.d/xsupplicant start, and survives a reboot thanks to chkconfig xsupplicant on, 802.1X authentication will take place automatically.
Listing 6
xsupplicant.conf
Testing
The wpa_supplicant package provides a means for testing the configuration:
wpa_supplicant -i eth0 -D wired -c /etc/wpa_supplicant/wired.conf
Now you need to create a wired.conf configuration file, as specified in Listing 7. Because 802.1X authentication is wire based, you can use version 2 of eapol_version and disable the access point scan.
Listing 7
wired.conf
The supplicant announces CTRL-EVENT-EAP-SUCCESS in the case of a successful authentication. To run the client permanently in the background and authenticate the client automatically in case of 802.1X ports, users need to modify /etc/network/interfaces, as shown in Listing 8 for Debian – assuming they use DHCP. Otherwise, change dhcp to static and define a static IP address. /etc/init.d/networking restart enables these settings. If the client achieves authorized state via a non-IEEE 802.1X port, the login attempt will be redundant, but the client will work normally.
Listing 8
Interfaces Enables DHCP
« Previous 1 2 3 4 Next »
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
![Learn More](https://www.linux-magazine.com/var/linux_magazin/storage/images/media/linux-magazine-eng-us/images/misc/learn-more/834592-1-eng-US/Learn-More_medium.png)
News
-
NVIDIA Released Driver for Upcoming NVIDIA 560 GPU for Linux
Not only has NVIDIA released the driver for its upcoming CPU series, it's the first release that defaults to using open-source GPU kernel modules.
-
OpenMandriva Lx 24.07 Released
If you’re into rolling release Linux distributions, OpenMandriva ROME has a new snapshot with a new kernel.
-
Kernel 6.10 Available for General Usage
Linus Torvalds has released the 6.10 kernel and it includes significant performance increases for Intel Core hybrid systems and more.
-
TUXEDO Computers Releases InfinityBook Pro 14 Gen9 Laptop
Sporting either AMD or Intel CPUs, the TUXEDO InfinityBook Pro 14 is an extremely compact, lightweight, sturdy powerhouse.
-
Google Extends Support for Linux Kernels Used for Android
Because the LTS Linux kernel releases are so important to Android, Google has decided to extend the support period beyond that offered by the kernel development team.
-
Linux Mint 22 Stable Delayed
If you're anxious about getting your hands on the stable release of Linux Mint 22, it looks as if you're going to have to wait a bit longer.
-
Nitrux 3.5.1 Available for Install
The latest version of the immutable, systemd-free distribution includes an updated kernel and NVIDIA driver.
-
Debian 12.6 Released with Plenty of Bug Fixes and Updates
The sixth update to Debian "Bookworm" is all about security mitigations and making adjustments for some "serious problems."
-
Canonical Offers 12-Year LTS for Open Source Docker Images
Canonical is expanding its LTS offering to reach beyond the DEB packages with a new distro-less Docker image.
-
Plasma Desktop 6.1 Released with Several Enhancements
If you're a fan of Plasma Desktop, you should be excited about this new point release.