Setup SSL VPN Road Warrior

Road Warriors are remote users who need secure access to the companies infrastructure. Ixolate uses OpenVPN for its SSL VPN Road Warrior setup and offers OTP (One Time Password) integration with standard tokens and Googles Authenticator.

Before you start

Before starting with the configuration of an OpenVPN SSL tunnel you need to have a working Ixolate installation with a unique LAN IP subnet for each side of your connection (your local network needs to be different than that of the remote network).

Network topology

The schema below describes the situation we are implementing. One client using an “external” ip address of 10.0.8.2/24 a firewall we are connecting to at 10.0.8.1/24 constructing a tunnel using 10.2.8.0/24 to reach 192.168.8.0/24.

nwdiag {

span_width = 90; node_width = 180; network { address = “10.0.8.0/24”; pclana [label=“Roadwarriorn10.2.8.2”,shape=“cisco.pc”]; fw [shape = “cisco.firewall”, address=“10.0.8.1/24”]; } network Ext { address = “192.168.8.0/24”; fw [shape = “cisco.firewall”, address=“192.168.8.1/24”]; pclanb [label=“Servern192.168.8.20”,shape=“cisco.pc”]; }

}

Preparations

Trust

In order to setup a tunnel on both ends, we need to configure certificates to warrant trust between both machines. We need a root CA that issues two leaf certificates, one for this server and one for a user.

Create a certificate chain using the following tutorial:

Setup Self-Signed Certificate Chains

• `Root CA`: SSL VPN CA
• `Leaf Certificate - Type Server`: Set the Common Name to the FQDN of this machine.
• `Leaf Certificate - Type Client`: Create a user with the same username as this certificates Common Name.

The root CA issues the leaf certificates directly; we do not need an intermediate CA.

Static keys

We create a static key and define it’s use in VPN › OpenVPN › Instances › Static Keys, for this example select auth as mode and click the gear button to generate one. Provide a description for this key.

Create a server instance

Now the generic setup is done, we can configure a new server type instance via VPN › OpenVPN › Instances

Note 1

Leave empty to bind to all addresses assigned to this machine or use a loopback address combined with a Destination NAT (Port Forward) when the external address is not static.

Note 2

When users are also required to use a one-time-password, just select an authentication server that supports the additional token.

Note 3

Selecting the “Strict User/CN Matching” option warrants only matching user/certificate can login, when sharing a single certificate between clients this option needs to be deselected.

Note 4

If you want all outgoing IP traffic to be redirected over the VPN, you can set the option to default. For this to work, a manual Source NAT rule must be created.

Next go to Firewall › Rules › WAN and add a rule to allow traffic on port 1194/UDP from the other host. At minimum we should add a rule similar to this one:

Finally we are going to allow traffic on the tunnel itself by adding a rule to Firewall › Rules › OpenVPN, for this example we keep it simple and add one to allow all, in which case we can save the defaults when adding a rule.

Export client profile

With the server in place it’s time to setup the client on Ixolate, for this we go to VPN › OpenVPN › Client Export and export a profile for the remote client.

Note 1

Most clients support the standard ovpn format, when using a tool like Viscosity from Sparklabs (https://www.sparklabs.com/viscosity/) you can also choose the proper type here.

Next client on the certificate with link user in the grid below and install the certificate on the client.

Test connectivity

After connecting the client, use the VPN: OpenVPN: Connection Status page to watch the status of the connected client. It should show the client with byte counters.

Now try to ping from Site A (10.0.8.20) to Site B (192.168.8.20).