On Tue, 2026/09/08 at 14:06:17 +0100, Joe wrote: > On Tue, 8 Sep 2026 11:41:27 +0200 > Nicolas George <[email protected]> wrote: > > > Vincent Lefevre (HE12026-09-08): > > > But on the problematic machine citron, getaddrinfo with AF_UNSPEC > > > returns only the IPv6 address. With IPv4, it returns the IPv4 > > > address, though. > > > > So next step is to examine the DNS requests made by the resolver to > > see if the issue is that it does not request IPv4 or that it does not > > get it as a reply. > > > > Regards, > > > > With IPv6 on the router and kernel disabled, a new installation of bind9 > still listens on IPv6 addresses. It still attempts IPv6 communications. > It has to explicitly be told not to. Apt attempts IPv6 first, again > unless told not to. > > I haven't found any other problems yet, as this is on a server and no > web browsing occurs. Apt obviously uses http access, but once name > resolution was fixed and it was told to use IPv4, there has been no > trouble. > > I expect at some point that my ISP will open up IPv6 access, but it is > currently giving no expected date.
If you want to prioritise the use IPv4 over IPv6, you can do so by editing /etc/gai.conf and changing: precedence ::1/128 50 precedence ::/0 40 precedence 2002::/16 30 precedence ::/96 20 precedence ::ffff:0:0/96 10 to precedence ::1/128 50 precedence ::/0 40 precedence 2002::/16 30 precedence ::/96 20 precedence ::ffff:0:0/96 100 which will then require a restart of resolver and apps that use getaddrinfo() calls. It shifts the priority of IPv4 from last to first. Use with caution, and remember where/why you done the change. -- Kind regards, /S
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