# documentation:2.0:authcas
Keywords: documentation,2.0,authcas

# CAS

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

## Presentation

LL::NG can delegate authentication to a CAS server. This requires Perl CAS module.

LL::NG can also act as CAS server, that allows one to interconnect two LL::NG systems.

LL::NG can also request proxy tickets for its protected services. Proxy tickets will be collected at authentication phase and stored in user session under the form:

`_casPT` serviceID = Proxy ticket value

They can then be forwarded to applications trough HTTP headers.

CAS authentication will automatically add a logout forward rule on CAS server logout URL in order to close CAS session on LL::NG logout.

## Configuration

In Manager, go in `General Parameters` > `Authentication modules` and choose CAS for authentication.

You can then choose any other module for users and password.

Then, go in `CAS parameters`:

- Authentication level: authentication level for this module.

Then create the list of CAS servers in the manager. For each, set:

- Server URL (required): CAS server URL (must use https://)
- Renew authentication (default: disabled): force authentication renewal on CAS server
- Gateways authentication (default: disabled): force transparent authentication on CAS server
- Display Name: Name to display. Required if you have more than 1 CAS server declared
- Icon: Path to CAS Server icon, used only if you have more than 1 CAS server declared
- Proxied services: list of services for which a proxy ticket is requested:
  - Key: Service ID
  - Value Service URL (CAS service identifier)

If no proxied services defined, CAS authentication will not activate the CAS proxy mode with this CAS server.