IPSec with IKEv2 setup guide

The following Strogswan configuration is known to work:

1. Create a config file in your strongswan ipsec.d directory e.g. ivpn.conf with the following

   conn ivpn
       keyexchange=ikev2
       right=gb.gw.ivpn.net
       rightid=gb.gw.ivpn.net
       rightsubnet=0.0.0.0/0
       rightauth=pubkey
       leftsourceip=%config
       leftauth=eap-mschapv2
       eap_identity=ivpnaccountID
       auto=start
       dpdaction=restart
   

   Change the right= and rightid= as appropriate for the server you want to connect to. The ivpnaccountID is case-sensitive.

2. Create a .secrets file e.g. ivpn.secrets in the strongswan ipsec.d directory e.g. ivpn.secrets with the following

   ivpnaccountID : EAP "ivpn"
   

   Note that there is a space either side of the colon :.

3. Depending on your Linux distribution and version, you may need to download some or all of the following certificates and store them in files located in your strongswan ipsec.d/cacerts directory:

   https://letsencrypt.org/certs/letsencryptauthorityx3.pem.txt
   https://letsencrypt.org/certs/lets-encrypt-x3-cross-signed.pem.txt
   https://letsencrypt.org/certs/trustid-x3-root.pem.txt
   https://letsencrypt.org/certs/isrgrootx1.pem.txt

4. Tell strongswan to restart or reload it’s config.