On Wed, May 13, 2026 at 1:20 PM Piotr Dobrogost <[email protected]> wrote: > > Hi, > > After I upgraded from OpenVPN 2.6 to OpenVPN 2.7 (as a part of the > upgrade from Fedora 43 to Fedora 44), the OpenVPN tunnel that had been > working without problems for months stopped working. The log of > OpenVPN looks normal, with the "Initialization Sequence Completed" > entry that always signals an established tunnel. However, no data gets > through; there is no response when pinging the tunnel’s remote > endpoint or remote DNS server. > After I disabled DCO on the client side (--disable-dco), the tunnel > started to work. > My question is: how could I find out that the culprit is DCO in the first > place?
Server I'm connecting with is OpenVPN 2.4.0 This looks like https://github.com/OpenVPN/openvpn/issues/422 Is the error in the log added in https://github.com/lstipakov/openvpn/commit/fa4083692fefb9c94ff9366cdabe56fa52c62b72 server side? I guess it is, as it's not present in my logs. If this error were logged on the client side, the situation would be clear, and the reason the tunnel does not work would be obvious. Btw, when you were checking this on Fedora 44 on your side, you must have used at least version 2.4.5 of the server, and that's why it was working for you. Regards, Piotr Dobrogost _______________________________________________ Openvpn-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/openvpn-users
