OUR SITES NetworkRADIUS FreeRADIUS

Configuring Authentication

Testing

Authentication

Now in another terminal window run on the FreeRADIUS server to test authentication:

cat <<'EOF' | radclient -x localhost auth testing123
User-Name = "john"
User-Password = "password"
EOF

Access-Accept

If this works you should see radclient report Access-Accept almost immediately without delay:

Sent Access-Request Id 39 from 0.0.0.0:47493 to 127.0.0.1:1812 length 44
  User-Name = john
  User-Password = password
Received Access-Accept Id 39 from 127.0.0.1:1812 to 0.0.0.0:47493 via lo length 26
  User-Name = "john"

On the FreeRADIUS debug terminal side, you should see something like:

...
(0)    ldap - Reserved connection (0)
(0)    ldap - EXPAND (uid=%{%{Stripped-User-Name} || %{User-Name}})
(0)    ldap - --> (uid=john)
(0)    ldap - Performing search in "dc=example,dc=com" with filter "(uid=john)", scope "sub"
(0)    ldap - Waiting for search result...
(0)    ldap - User object found at DN "uid=john,ou=people,dc=example,dc=com"
(0)    ldap - Processing user attributes
(0)    ldap -   &control.Password.With-Header += password
(0)    ldap - Released connection (0)
(0)    ldap (updated)
...
(0)    pap - No {...} in &Password.With-Header, re-writing to Password.Cleartext
(0)    pap - Normalized &control.Password.With-Header -> &control.Password.Cleartext
(0)    pap - Removing &control.Password.With-Header
(0)    pap - Setting &control.Auth-Type = pap
(0)    pap (updated)
(0)  } # recv Access-Request (updated)
(0)  Running 'authenticate pap' from file /usr/local/etc/raddb/sites-enabled/default
(0)  authenticate pap {
(0)    pap - Login attempt with password
(0)    pap - Comparing with "known-good" Password.Cleartext (8)
(0)    pap - User authenticated successfully
(0)    pap (ok)
(0)  } # authenticate pap (ok)
(0)  Running 'send Access-Accept' from file /usr/local/etc/raddb/sites-enabled/default
...

Here FreeRADIUS is describing what it did:

  1. used the ldap module

    • searched for (uid=john) in dc=example,dc=com

      • this is doing the same as the following that you could run on the CLI

        ldapsearch -LL -H ldap://localhost -x -D cn=freeradius,dc=example,dc=com -w mypassword -b dc=example,dc=com '(uid=john)'

    • found uid=john,ou=people,dc=example,dc=com

      • if for you no user is found, but you know the user is in your directory, recheck the user { …​ } section in raddb/mods-available/ldap as you may have a filter or attribute configuration set incorrectly

    • found some useful attributes associated with that user

      • the password which it placed into control.Password.With-Header

      • as RADIUS attributes were changed, it returns updated as a result code to unlang

  2. the module pap was used

    • it found a suitable password to use in &Password.With-Header

      • populates &control.Password.Cleartext

      • the module decides it has everything it needs to do authentication so sets &control.Auth-Type = pap

      • as RADIUS attributes were changed, it returns updated as a result code to unlang

  3. the authenticate section runs and hands off to pap as &control.Auth-Type = pap was set earlier

    • &control.Password.Cleartext is compared to &request.User-Password

    • matches so ok is returned

  4. we return Access-Accept as ok was returned to unlang

This worked as the LDAP credentials used by FreeRADIUS to connect to the LDAP server is able to extract a the userPassword attribute; as could been seen from the example ldapsearch command provided earlier.

Access-Reject

If this fails, the response will be delayed by one second and Access-Reject will be returned:

Debug : Sent Access-Request Id 130 from 0.0.0.0:49353 to 127.0.0.1:1812 length 44
Debug : Received Access-Reject Id 130 from 127.0.0.1:1812 to 0.0.0.0:49353 via lo length 20
(0) -: Expected Access-Accept got Access-Reject

You should now look to the output of the debugging from the FreeRADIUS terminal window which may show something like:

(0)    ldap - Reserved connection (0)
(0)    ldap - EXPAND (uid=%{%{Stripped-User-Name} || %{User-Name}})
(0)    ldap - --> (uid=john)
(0)    ldap - Performing search in "dc=example,dc=com" with filter "(uid=john)", scope "sub"
(0)    ldap - Waiting for search result...
(0)    ldap - User object found at DN "uid=john,ou=people,dc=example,dc=com"
(0)    ldap - Processing user attributes
(0)    ldap - Released connection (0)
(0)    ldap (ok)
(0)    expiration (noop)
(0)    pap - WARNING: No "known good" password found for the user.  Not setting Auth-Type
(0)    pap - WARNING: Authentication will fail unless a "known good" password is available
(0)    pap (noop)
(0)  } # recv Access-Request (ok)
(0)  ERROR: No Auth-Type available: rejecting the user.
(0)  Running 'send Access-Reject' from file /usr/local/etc/raddb/sites-enabled/default

Here FreeRADIUS describes it:

  1. used the ldap module

    • searched for (uid=john) in dc=example,dc=com

    • found uid=john,ou=people,dc=example,dc=com

    • did not find any useful attributes associated with that user

    • module was successful in operation, but changed no RADIUS attributes so returns ok

  2. the module expiration was used, but it had no effect (noop)

  3. the module pap was used

    • it finds no suitable password RADIUS attributes to use

    • as it makes no changes, the module returns noop

  4. no Auth-Type is set, so FreeRADIUS rejects the request (no even attempting to authenticate)

  5. returns Access-Reject

This occurs as the LDAP credentials used by FreeRADIUS to connect to the LDAP server is unable to extract a the userPassword attribute; as could been seen from the example ldapsearch command provided earlier.

You have two options available to you here (Ctrl-C the running FreeRADIUS server, make the change and restart):

  1. change the permissions of the LDAP credentials used so that FreeRADIUS can read the LDAP userPassword attribute

    • this is the recommended option

    • fixing this, means you should see Access-Accept as described above

  2. configure FreeRADIUS to attempt to 'bind' (LDAP language for 'login') as the user in the RADIUS request

    • do this by editing /usr/local/etc/raddb/sites-available/default

    • amend by adding after the call to ldap in recv Access-Request { …​ } section, so that it looks like:

      -ldap
if ((ok || updated) && &User-Password) {
  &control.Auth-Type := ldap
}

    • FreeRADIUS is now configured to attempt to LDAP bind if the ldap module finds a user and the RADIUS request contains a User-Password RADIUS attribute

If you use LDAP bind’ing to perform user authentication, then when radclient receives `Accept-Accept', the FreeRADIUS debug terminal will look like:

(0)    ldap - Reserved connection (0)
(0)    ldap - EXPAND (uid=%{%{Stripped-User-Name} || %{User-Name}})
(0)    ldap - --> (uid=john)
(0)    ldap - Performing search in "dc=example,dc=com" with filter "(uid=john)", scope "sub"
(0)    ldap - Waiting for search result...
(0)    ldap - User object found at DN "uid=john,ou=people,dc=example,dc=com"
(0)    ldap - Processing user attributes
(0)    ldap - Released connection (0)
(0)    ldap (ok)
(0)    if ((ok || updated) && &User-Password) {
(0)      &control.Auth-Type := ldap
(0)    } # if ((ok || updated) && &User-Password) (noop)
(0)    expiration (noop)
(0)    pap - WARNING: No "known good" password found for the user.  Not setting Auth-Type
(0)    pap - WARNING: Authentication will fail unless a "known good" password is available
(0)    pap (noop)
(0)  } # recv Access-Request (ok)
(0)  Running 'authenticate ldap' from file /usr/local/etc/raddb/sites-enabled/default
(0)  authenticate ldap {
(0)    ldap - Login attempt with password
(0)    ldap - Reserved connection (1)
(0)    ldap - Login attempt by "john"
(0)    ldap - Using user DN from request "uid=john,ou=people,dc=example,dc=com"
(0)    ldap - Waiting for bind result...
(0)    ldap - Bind successful
(0)    ldap - Bind as user "uid=john,ou=people,dc=example,dc=com" was successful
(0)    ldap - Released connection (1)
(0)    ldap (ok)
(0)  } # authenticate ldap (ok)
(0)  Running 'send Access-Accept' from file /usr/local/etc/raddb/sites-enabled/default

Here FreeRADIUS is describes it:

  1. used the ldap module

    • searched for (uid=john) in dc=example,dc=com

    • found uid=john,ou=people,dc=example,dc=com

    • did not find any useful attributes associated with that user

    • module was successful in operation, but changed no RADIUS attributes so returns ok

  2. &control.Auth-Type := ldap was set as the ldap module was successful in finding a user

  3. the module expiration was used, but it had no effect (noop)

  4. the module pap was used

    • it finds no suitable password RADIUS attributes to use

    • as it makes no changes, the module returns noop

  5. the authenticate section runs and hands off to ldap as &control.Auth-Type = ldap was set earlier

    • attempts to LDAP bind as uid=john,ou=people,dc=example,dc=com

    • successful so ok is returned

  6. we return Access-Accept as ok was returned to unlang