proxy_pass behavior

Jim Popovitch jimpop at
Thu Mar 27 17:12:18 UTC 2014

On Thu, Mar 27, 2014 at 12:59 PM, Maxim Dounin <mdounin at> wrote:
> Hello!
> On Thu, Mar 27, 2014 at 12:29:03PM -0400, Jim Popovitch wrote:
>> Should proxy_pass retry ipv4 if ipv6 fails?   Currently (1.5.12), it
>> does not, and there is no way to force proxy_pass to always use ipv4.
> In no particular order:
> - The proxy_next_upstream is expected to retry by default.

Yes, that works if the host name has 2 or more A  OR  2 or more AAAA
records.  proxy_next_upstream does not appear to transition to the
next protocol (i.e. from ipv4 to ipv6)

> - There _is_ a way to force proxy_pass to always use ipv4 - you
>   should configure your system accordingly, and
>   getaddrinfo(AI_ADDRCONFIG) as used by nginx will do the right
>   thing.  E.g., on Linux net.ipv6.conf.all.disable_ipv6 can be set
>   to disable use of ipv6.

:-)  That's unacceptable!!  :-)   I don't want people to disable ipv6,
I want proxy_pass to use ipv6 and upon failure use ipv4.  ;-)

-Jim P.

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