How Are VPN Tunnels Counted?
Knowledge Base ID: KB4204
Version: 2.0
Published: 07 Oct 2008
Updated: 07 Oct 2008
Categories: . NS-5GT
. NS-5XP
. NS-5XT
. NS-25
. NS-50
. NS-204
. NS-208
. NS-5200
. NS-5400
. ScreenOS

Summary:
How Are VPN Tunnels Counted?

Problem or Goal:

Solution:

Note: This article applies to ScreenOS 4.0 and higher.

For IKE VPN tunnels, you can have multiple policies per tunnel. Each network included in a tunnel will constitute one Security Association (SA). Therefore, you can have multiple SAs per VPN tunnel. In a normal LAN to LAN VPN tunnel, the number of gateways configured equals the number of tunnels.

Counting of tunnels with dial-up VPN users is different. When creating dial-up VPN users, each user will count as one VPN gateway. If using a dial-up VPN group, the dial-up group IKE entry will count as one VPN gateway, and additional dial-up users will use up another VPN tunnel.

For example, there is a NetScreen-5XP that has three LAN to LAN IKE tunnels, two manual key tunnels, and one dial-up VPN group IKE entry, with 20 members in the VPN group. If no dial-up VPN users are connected, the effective number of tunnels would be six tunnels. For a NetScreen-5XP, the limit is 10 VPNs, which means there are four VPNs left for the dial-up VPN users.



Purpose:
Troubleshooting