libapache2-mod-auth-cas software package provides CAS authentication module for Apache2, you can install in your Debian 8 (Jessie) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install libapache2-mod-auth-cas
libapache2-mod-auth-cas is installed in your system.
Make ensure the libapache2-mod-auth-cas package were installed using the commands given below,
$ sudo dpkg-query -l | grep libapache2-mod-auth-cas *
You will get with libapache2-mod-auth-cas package name, version, architecture and description in a table
| Distro | Debian 8 jessie |
| Section | Web Servers |
| Package | libapache2-mod-auth-cas |
| Version | 1.0.9.1-4 |
| Description | CAS authentication module for Apache2 |
| Sub Section | HTTPD |