Install the strongswan package: yum install strongswan
Note: in the latest versions (CentOS 7), the strongswan package is not available in the default repositories of the operating system. Therefore, it is recommended to install the Epel repository before installing Strongswan using the command: yum install epel-release.noarch
Download the following configuration files: a) /etc/strongswan/ipsec.conf b) /etc/strongswan/ipsec.secrets c) /etc/strongswan/strongswan
Edit the ipsec.conf file and replace the username with the correct one in the eap_identity parameter
Edit the ipsec.secrets file and enter the user's access credentials, replacing the password and username with the correct ones. Note: you must replace username@ciencias.ulisboa.pt with login@domain (or email address), as well as the password valid for the user. You must keep the quotation marks in the configuration. Students or other users with an account in the students domain should use a username of the type username@alunos.ciencias.ulisboa.pt
Download the intermediate CA certificate from the following link (TrustedRoot) and save it to: /etc/strongswan/ipsec.d/cacerts/
To start or end the VPN session, simply run: a) sudo strongswan up ciencias (to start the VPN session) b) sudo strongswan down ciencias (to end the VPN session)