The OpenVPN server (community edition) doesn't support a "max connected" time. This simple script will generate a list of users currently connected to the VPN and kill their session automatically once they reach the max connected time.

Requirements:

• OpenVPN community edition
• nc
• The 'management' value defined on in OpenVPN's server.conf
  
  

[root@vpn:/root]$ grep management /etc/openvpn/server/server.conf
management 127.0.0.1 7505
[root@vpn:/root]$

Install:

• Download kill_vpn_clients.sh and place it on your server
• Edit the PORT, KILLTIME and TMPFILE to meet your specific needs
  

PORT - Port of the "management" OpenVPN interface.
KILLTIME - Number of seconds where it should kill a VPN session, default is 12 hours.
TMPFILE - A temporary file used to parse the connected users

• Add it to cron to run $x minutes/hours
  

echo '0 * * * * root /root/kill_vpn_clients.sh >> /var/log/kill_vpn_clients.log' > /etc/cron.d/kill_vpn_clients