L2TP over IPsec VPN client setup

L2TP/IPsec VPN client setup

1 Linux

1.1 Gentoo

1.1.1 NetworkManager

• Open the NetworkManager UI, then:
  • Go to Network > VPN. Click +.
  • Select Layer 2 Tunneling Protocol (L2TP).
  • You can choose a name for the VPN.
  • Enter Your VPN Server IP for the Gateway.
  • Enter Your VPN Username for the User name.
  • Right-click the ? in the Password field, select Store the password only for this user.
    • You might want to use Store password for all users.
  • Enter Your VPN Password for the Password.
  • Leave the NT Domain field blank.
  • Click the IPsec Settings… button.
  • Check the Enable IPsec tunnel to L2TP host checkbox.
  • Leave the Gateway ID field blank.
  • Enter Your VPN IPsec PSK for the Pre-shared key.
  • Then click Add to save the VPN connection information.

1.1.2 Strongswan interactions

• By default, strongswan is built with capabilities support and the ability to run as an unprivileged user.
• However, capabilities are not configured in NetworkManager.
• As a result, the connection is not established.
• You can solve the problem as follows:
  • either install strongswan without capabilities support and the ability to run as an unprivileged user:

    USE="-caps -non-root" emerge strongswan
    

  • either build NetworkManager with capabilities support (see https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1053).