# documentation:2.0:authapache
Keywords: documentation,2.0,authapache

# Apache

Authentication | Users | Password
--- | --- | ---
✔ |  |

## Presentation

LL::NG can delegate authentication to Apache, so it is possible to use any Apache authentication module, for example Kerberos, Radius, OTP, etc.

Apache authentication module will set the `REMOTE_USER` environment variable, which will be used by LL::NG to get authenticated user.

## Configuration

### LL::NG

In General Parameters > Authentication modules, choose `Apache` as authentication backend.

You may want to failback to another authentication backend in case of the Apache authentication fails. Use then the Multiple authentication module, for example:

    Apache;LDAP

In this case, the Apache authentication module should not require a valid user and not be authoritative, else Apache server will return an error and not let LL::NG Portal manage the failback authentication.

### Apache

The Apache configuration depends on the module you choose, you need to look at the module documentation, for example:

- Kerberos
- NTLM
- Radius
- …

## Tips

### Kerberos

The Kerberos configuration is quite complex. You can find some configuration tips on this page.

### Compatibility with Identity Provider modules

When using IDP modules (like CAS or SAML), the activation of Apache authentication can alter the operation. This is because the client often need to request directly the IDP, and the Apache authentication will block the request.

In this case, you can add in the Apache authentication module:

          Satisfy any
          Order allow,deny
          allow from APPLICATIONS_IP

This will bypass the authentication module for request from APPLICATIONS_IP.