DSommers has released an new Kernel Mod, and It looks like it is working again. However, Secure Boot has to be turned off for the OpenVPN host to use it as the Kernel mod is not signed.
You need to update the package kmod-ovpn-dco
this should remove the old package and replace it with the new.
Turn off secure boot on your host, and reboot
modprobe ovpn-dco-v2
then
lsmod | grep vpn
should show something like
ovpn_dco_v2 90112 0
ip6_udp_tunnel 16384 1 ovpn_dco_v2
udp_tunnel 24576 1 ovpn_dco_v2
Then, restart the OpenVPN service and test
You should see the following references to DCO in your openvpn.log file (at VERB 4)
2023-10-13 16:10:55 us=954458 OpenVPN 2.6.6 x86_64-redhat-linux-gnu [SSL (OpenSSL)] [LZO] [LZ4] [EPOLL] [PKCS11] [MH/PKTINFO] [AEAD] [DCO]
2023-10-13 16:10:55 us=954472 library versions: OpenSSL 1.1.1k FIPS 25 Mar 2021, LZO 2.08
2023-10-13 16:10:55 us=954530 DCO version: copr:0.2.20230426.3.el8
......
2023-10-13 16:10:56 us=2438 net_iface_new: add tun0 type ovpn-dco
2023-10-13 16:10:56 us=3423 DCO device tun0 opened
......
