Allow one-time login per user
You can set the SSL VPN tunnel such that each user can only log into the tunnel one time concurrently per user per login. That is, once logged into the portal, they cannot go to another system and log in with the same credentials again.
To allow one-time login per user - web-based manager:
Go to VPN > SSL > Portals, select a portal, and enable Limit Users to One SSL-VPN Connection at a Time. It is disabled by default.
To allow one-time login per user - CLI:
config vpn ssl web portal
edit <portal_name>
set limit-user-logins enable
end
See Also