- IPsec: Setup OPNsense for IKEv1 using XAuth
- Step 1 - Create Certificates (only for RSA variants)
- Step 2 - Mobile Clients
- Step 3 - Phase 1 Mobile Clients
- Step 3 - Phase 2 Mobile Clients
- Step 4 - Add IPsec Users
- Step 5 - Add client certificate (for Mutual RSA)
XAuth was an addition to IKEv1 supporting user authentication credentials additionally to pre-shared keys or certificates. There are three different types supported by OPNsense which we will describe here.
Mutual PSK + XAuth: You define a pre-shared key which is the same for every user and after securing the channel the user authentication via XAuth comes into play. Mutual RSA + XAuth: Instead of using a pre-shared key, every device needs a client certificate to secure the connection plus XAuth for authentication. This is the most secure variant for IKEv1/XAuth but also with the most work to do. Hybrid RSA + XAuth: Hybrid RSA is the same as Mutual, without the need for a client certificate. Only the server will be authenticated (like using HTTPS) to prevent man-in-the-middle attacks like with Mutual PSK. It is more secure than PSK but does not need the complete roll-out process like with Mutual RSA.
We assume you have read the first part at IPsec: Setup Remote Access
For Mutual RSA + XAuth and Hybrid RSA + XAuth you need to create a Root CA and a server certificate for your Firewall.
Go toand click Add. Give it a Descriptive Name and as Method choose Create internal Certificate Authority. Increase the Lifetime and fill in the fields matching your local values. Now go to and create a new certificate for the Firewall itself. Important is to change the Type to server. The Common Name can be the hostname of the Firewall and set as Alternative Name the FQDN your Firewall how it is known to the WAN side. This is most important as your VPN will drop when the FQDN does not match the ones of the certificate.
If you already have a CA roll out a server certificate and import the CA itself viaand the certificate with the key in .
First we will need to setup the mobile clients network and authentication source. Go to
For our example will use the following settings:
|Enable||checked||check to enable mobile clients|
|User Authentication||Local Database||For the example we use the Local Database|
|Group Authentication||none||Leave on none|
|Virtual Address Pool||10.10.0.0/24||Enter the IP range for the remote clients|
You can select other options, but we will leave them all unchecked for this example.
Save your settings and select Create Phase1 when it appears. Then enter the Mobile Client Phase 1 setting.
|Connection method||default||default is ‘Start on traffic’|
|Key Exchange version||V1||XAuth only works on V1|
|Interface||WAN||choose the interface connected to the internet|
|Description||MobileIPsec||freely chosen description|
|Authentication method||XAuth||Choose one of the three available options|
|Negotiation mode||Main Mode||Use Main Mode here|
|My identifier||Distinguished Name||Set the FQDN you used within certificate, for PSK use “My IP address”|
|Pre-shared Key||Shared secret||For Mutual PSK + XAuth use this PSK, otherwise certificate below|
|My Certificate||Certificate||Choose the certificate from dropdown list, only valid for RSA variants|
|Encryption algorithm||AES||For our example we will use AES/256 bits|
|Hash algoritm||SHA1, SHA256||SHA1 and SHA256 for compatibility|
|DH key group||1024, 2048 bit||1024 and 2048 bit for compatibility|
|Lifetime||28800 sec||lifetime before renegotiation|
Advanced Options are fine by default.
Save your settings.
Press the button that says ‘+ Show 0 Phase-2 entries’
You will see an empty list:
Now press the + at the right of this list to add a Phase 2 entry.
|Mode||Tunnel IPv4||Select Tunnel mode|
|Description||MobileIPsecP2||Freely chosen description|
|Protocol||ESP||Choose ESP for encryption|
|Encryption algorithms||AES / 256||For this example we use AES 256|
|Hash algorithms||SHA1, SHA256||Same as before, mix SHA1 and SHA256|
|PFS Key group||off||Most mobile systems do not support PFS in Phase2|
Save your settings and Enable IPsec, Select:
If you already had IPsec enabled and added Road Warrior setup, it is important to restart the whole service via services widget in the upper right corner of IPSec pages or viasince applying configuration only reloads it, but a restart also loads the required modules of strongSwan.
Go toand press the + sign in the lower right corner to add a new user.
Enter the following into the form:
Save to apply.
This step is only needed for Mutual RSA + XAuth!
Go toand create a new client certificate. Just click Add, choose your CA and probably increase the lifetime. Everything else besides the CN can be left default. Give a Common Name and Save. Download the newly created certificate as PKCS12 and export it to you enduser device.