Securing Network Access with 802.1X, Radius, and LDAP

SHUTTING OUT STRANGERS

Article from Issue 52/2005
Author(s):

The Radius protocol is typically used to authenticate users in dial-up scenarios. But Radius is also useful in LAN environments: in combination with 802.1X, Radius forces users to authenticate at a low level before the switch opens up a port.

Attacks from internal networks are dangerous and more difficult to prevent than external attacks. An attacker who plugs in to an internal network with a laptop gains wide-ranging access to network data. One way of preventing an attack is to implement an authentication function in OSI Layer 2 using the 802.1X [1] protocol. An 802.1X-capable switch and a Freeradius server are all you need to implement Layer 2 authentication. Because Layer 2 authentication operates at the level of the local, physical network, it prevents an intruder from even using the physical network without authentication. Radius (Remote Authentication Dial-in User Service Protocol) responses from a Linux server typically include the IP address and standard gateway for the user, but the protocol has more potential. You can use a Radius server to assign a VLAN to the user’s switch port. This technique avoids the need for a complex router infrastructure, but still restricts the size of the broadcast domain.

Buy this article as PDF

Express-Checkout as PDF
Price $2.95
(incl. VAT)

Buy Linux Magazine

SINGLE ISSUES
Print Issues
Digital Issues
 
SUBSCRIPTIONS
Print Subs
Digisubs
 
TABLET & SMARTPHONE APPS
Get it on Google Play

US / Canada

Get it on Google Play

UK / Australia

Related content

  • IEEE 802.1X

    Did you think the IEEE 802.1X standard is only for wireless? We show you how to set up a network access control system on a wired network with IEEE 802.1X and a FreeRADIUS server.

    more »
  • Uranos Installation Framework

    The virtualization breakthrough has not reduced the number and diversity of operating systems that admins must install and manage. Uranos server sets out to give administrators of complex operating system zoos more freedom.

    more »
  • Hotspotter

    Security experts are always concerned with WLAN access points, but they sometimes forget that the client is also open to attack. Public hotspots make it quite easy for attackers to hijack connections, as the Hotspotter tool demonstrates.

    more »
comments powered by Disqus

Visit Our Shop

Trial Subscription

Digital Subscription

Subscribe

Direct Download

Read full article as PDF:

Freeradius_802.1X.pdf (295.87 kB)

DevOps

News

Tag Cloud

Administration Community Events Hardware Linux Linux New Media Linux Pro Magazine Mobile Programming Software Ubuntu Web Development Windows free software open source
njobs Europe
What:
Where:
Country:
Njobs Netherlands Njobs Deutschland Njobs United Kingdom Njobs Italia Njobs France Njobs Espana Njobs Poland
Njobs Austria Njobs Denmark Njobs Belgium Njobs Czech Republic Njobs Mexico Njobs India Njobs Colombia