Tutorial: How to Configure IPSec Site-to-Site VPN Tunnel on OPNsense?

VPN
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Dear OPNsense community,

IPSec is a collection of communication protocols that provide secure connections over a network. The phrase “IPsec” is an abbreviation where “IP” represents “Internet Protocol” and “sec” represents “secure.”

OPNsense provides VPN connectivity for both branch offices and remote users (Road-Warrior). Setting up a single, secure private network that connects several branch offices to a central location is simply accomplished using the OPNsense web user interface.

This guide will explain the process of configuring an IPsec site-to-site VPN tunnel using an OPNsense firewall.

Best Regards,

Zenarmor Team

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I can’t think of any reason to prefer IPSec over Wireguard or OpenVPN for S2S VPN between OPNSense boxes.

It’s way more convoluted to set up and performs worse than both.

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  1. I needed IPSec because the main office router doesn’t support wireguard
  2. IPSec is very close to wireguard in terms of performance. OpenVPN is not.
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You may find WireGuard and OpenVPN tutorials below:

https://www.zenarmor.com/docs/network-security-tutorials/how-to-setup-wireguard-on-opnsense

https://www.zenarmor.com/docs/network-security-tutorials/how-to-install-openvpn-with-mfa-in-opnsense

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  1. I needed IPSec because the main office router doesn’t support wireguard

Quoting me: S2S VPN between OPNSense boxes.

Connecting routers that don’t support either Wireguard or OpenVPN is the only good reason to use IPSec on OPNSense.