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After upgrading to Bionic, OpenVPN gives me the following error when connecting to my company's VPN

nm-openvpn[3360]: OpenSSL: error:140AB18E:SSL routines:SSL_CTX_use_certificate:ca md too weak

Connecting to VPN is not possible.

Yes I know that my company IT uses crappy old certificates and they should upgrade, but still I need to connect to the VPN otherwise I cannot do my work :)

How to fix?

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WARNING

This solution is only for users who cannot upgrade the VPN server. If you have admin access to your VPN server, please upgrade it and generate new keys, otherwise you will lose VPN security!

You need to add the following options in your OpenVPN config file:

tls-cipher "DEFAULT:@SECLEVEL=0"
remote-cert-tls server

This seems to not be possible with the network-manager GUI tool (correct me if I'm wrong), so you need to export your network-manager config to a file using this command:

nmcli c export MyVPN > ~/myvpn.ovpn

Then add the two options mentioned above to the end of the file, and launch openVPN from command line using this command:

sudo openvpn --config ~/myvpn.ovpn

Once you verify that the connection is working again, you can import back your unpdated configuration file and continue to use the Network Manager to setup the tunnel (thanks Eineki):

nmcli c import type openvpn file myvpn.ovpn
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  • Once you verify that the connection is working again, you can import back your unpdated configuration file with sudo nmcli c import type openvpn file <name or your .ovpn file> and continue to use the Network Manager to setupp the tunnel
    – Eineki
    Nov 3, 2018 at 19:52
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    This will disable all VPN security (not recommended).
    – xinthose
    Feb 5, 2019 at 15:11
  • @xinthose do you have any better recommendation?
    – Bastian Voigt
    Feb 6, 2019 at 14:44
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    @xinthose yeah, as I wrote in my question. I know company IT should upgrade the OpenVPN server but they don't do it and I still need to connect to VPN for doing my work. Of course, if you have admin access to the VPN server you should upgrade this first!
    – Bastian Voigt
    Feb 11, 2019 at 10:52
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    For me this didn´t work in ubuntu 22.04. Extra lines frm ovpn file are not picked up in networkmanager config files. Had to add tls-cipher=DEFAULT:@SECLEVEL=0 line to .nmconfig file in /etc/NetworkManager/system-connections and reload with nmcli. Now it does work
    – Bass850
    May 4, 2022 at 14:21

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