VPN Setup in "out of path" deployment style

  • Dear Team,

    I plan to setup PFSENSE as a VPN Server in a "out of path" style.
    My existing infra already has PFSENSE as firewall, but dont plan to include the VPN function into this main firewall.
    Plan to deploy another PFSENSE as a dedicated VPN server to cater for a group in my company.
    Any suggestions? How many network interfaces needed for this deployment?