On 21/04/2020 18:34, Claus Assmann wrote: > Thanks for the reply, below is the output, It seems it only fails > because the host doesn't support IPv6? Yes - it does seem to be an IPv6 problem. I don't recall any recent changes in this area. Were you successfully able to run the tests with previous versions of OpenSSL? Looks like the failing call is here: if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, (const void *)&on, sizeof(on)) != 0) { To which we get an errno indicating "Invalid argument". So it looks like your host has the relevant IPV6 macros defined (otherwise we would have got a compilation failure) - but doesn't understand them when used. If you're not using IPv6 on that host and this is the only test failure then it can probably be safely ignored. Matt