Hi, On Tue, Sep 08, 2026 at 05:40:35AM +0200, Vincent Lefevre wrote: > On a machine without IPv6 support (IPv6 disabled in the kernel, > and no IPv6 addresses), how to prevent programs from using IPv6 > by default?
In Linux, programs do not try to use IPv6 unless the system has at least one global scope IPv6 address. Since IPv6 has been in the Linux kernel for decades, if this mechanism were faulty, we would be inundated with problem reports all day every day. It should not be required to do gross hacks like messing with gai.conf or hacking your DNS resolver to not return AAAA records. The default gai.conf is fine for systems that don't have IPv6, and it is normal to see AAAA responses in DNS. I haven't seen anywhere in this thread that you have shown us the output of $ ip address show to show us all addresses on your system. It's possible I missed it, and if so I apologise. Either way, please could you check it again to see if there are any global scope IPv6 addresses there. The issue is that either your system is broken in some bizarre and rarely seen way, or else there is an IPv6 address there that you weren't expecting. Note that IPv6 addresses can be acquired in several ways without your positive action, e.g. router advertisements and DHCP. Thanks, Andy -- https://bitfolk.com/ -- No-nonsense VPS hosting
