[SOLVED] Set tls-cipher for OpenVPN in Kubuntu 23.10

[gugani]

New install of Kubuntu 23.10. In previous releases to add the OpenVPN connection I do:

1: Add the VPN connection as normal using the Network Manager GUI
2: Edit the connection file in /etc/NetworkManager/system-connections/(connectionname).nmconnection where (connectionname) is the name of your VPN conection
3: In the [vpn] section, beneath the line that starts ca=, add a new line reading
tls-cipher=DEFAULT:@SECLEVEL=0
4: Save the file
5: Enter the command systemctl restart NetworkManager

But now in 23.10 that is not working. There is info about the change in the release notes:

NetworkManager now uses Netplan as its default settings-storage backend. On upgrade, all connection profiles from /etc/NetworkManager/system-connections/ are transparently migrated to /etc/netplan/90-NM-*.yaml and become ephemeral, Netplan-rendered connection profiles in /run/NetworkManager/system-connections/. Backups of the original profiles are automatically created in /var/lib/NetworkManager/backups/ (read more at NetworkManager YAML settings backend 22 and LP: #1985994 7).

I am trying to add the configuration in the already existing /etc/netplan/90-NM-*.yaml, but I cannot find the option equivalent in Netplan to the tls-cipher=DEFAULT:@SECLEVEL=0 option in NetworManager.
Could someone give me some advice. Greetings.

[gugani]

Now I feel a little stupid, I realized that tls-cipher is an option in the OpenVPN configuration, not NetworkManager. I added the option to the ovpn file:

tls-cipher "DEFAULT:@SECLEVEL=0"

Then I added it via Network Manager. By the way, you can use the gui or in cli like this:

nmcli connection import type openvpn file file.ovpn

Now I can check the option I was looking for automatically created in /etc/netplan/90-NM-*.yaml:

vpn.tls-cipher:"DEFAULT:@SECLEVEL=0"

Note:
For GNOME 43+ (Debian 12, Ubuntu 23.04 etc) you can add some parameters (e.g. DEFAULT:@SECLEVEL=0") via GUI.
This way NetworkManager service restart is not required.

Connection settings > Identity > Advanced > TLS Authentication > TLS cipher string)