For example I'm reading something right now that says: "The authentication server is a RADIUS server, which authenticates virtual machines through a Lightweight Directory Access Protocol (LDAP) database."

I thought that to authenticate you either use Radius OR LDAP, not both. Can someone straighten my head?


1 Answer 1


LDAP is a database with user information (including passwords). Radius is a protocol for authentication (and other things) but does not contain any user information by itself. This means you could use Radius to authenticate against various kinds of password storage, including an LDAP database.

Support for Radius can be found in lots of devices and with simple interface any authentication protocol can be used which is supported by the Radius server. Depending on the radius server this can be simple password storage, LDAP, 2FA... . Thus if a specific system directly supports LDAP authentication you can use it, if it supports only Radius (more common) than you could use a Radius server with LDAP support and this way get the LDAP authentication to the system.

  • Ah so if LDAP is supported then you should only use LDAP and not Radius? i.e. Radius is not needed?
    – User104163
    Jul 15, 2016 at 19:50
  • 1
    @ponglenis: if your system all have LDAP support and all you need is LDAP and you don't need any of the additional features of Radius (like accounting) then there is no need to make the system more complex by adding Radius. Jul 15, 2016 at 20:00
  • Sorry for late reply. Isn't Radius more secure and less taxing on the network bandwidth?
    – User104163
    Jul 16, 2016 at 17:18
  • @ponglenis: no it isn't and I have no idea why you think it would. Jul 16, 2016 at 17:21
  • cdn.selinc.com//assets/Literature/Publications/…: "Network resources used by the two protocols are also quite different (see Table 2).
    – User104163
    Jul 16, 2016 at 17:44

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .