Bug: Missing Aggressive Mode in GUI

[jobs-git]

As the title says

[dkosovic]

I thought Aggressive Mode is mainly recommended for use with XAUTH and not with PSK to avoid offline brute force attack of the PSK, which isn't an issue with Main Mode as it doesn't leak the ID in clear text.

Extract from:

• https://[libreswan](https://libreswan.org/man/ipsec.secrets.5.html).org/man/ipsec.secrets.5.html

  An additional complexity arises in the case of authentication by preshared secret in IKEv1 Main Mode: the responder will need to look up the secret before the Peer's ID payload has been decoded, so the ID used will be the IP address. IKEv1 Aggressive Mode (aggrmode=yes) can be used to work around this, at the price of leaking the ID in the clear and allowing a brute force attack against the PSK to be performed offline. PSKs are the least secure authentication method and should be avoided.

As the Windows built-in L2TP VPN client doesn't use Aggressive Mode, would there be many L2TP servers that use Aggressive Mode, or IPsec IKEv1 servers that use Aggressive mode but don't use XAUTH?

The NetworkManager-vpnc and NetworkManager-libreswan VPN clients I believe use Aggressive Mode with XAUTH (or in the NetworkManager-libreswan case just for IKEv1 and not IKEv2).