I configured “L2TP over IPsec” on the Fortigate device. I used the following resource for this configuration. My VPN connection is working. But when I start the VPN connection, my internet connection is disconnected and I can only connect to the networks I VPN.
Can anyone help?
https://docs.fortinet.com/document/fortigate/7.2.3/administration-guide/386346/l2tp-over-ipsec
Did you configured the necessary firewall policy for internet access? This will be a policy allowing traffic from the tunnel interface to you WAN interface with NAT. Source will be the VPN subnet, destination will be all.
Thanks, this worked. But I don’t understand why this rule is necessary. Can you share a source on the subject?
An L2TP VPN doesn’t install routes on the client workstation like an SSL VPN client would, so split tunneling is not possible without some client side configuration. This means ALL traffic from that client gets tunneled, included internet access. Therefore you have to allow that access on the Fortigate. This is the default behavior for an L2TP tunnel.