CentOS - Jun 2018 - /etc/gai.conf fails to prefer IPv4 over IPv6 for NFS

In article <bc751efa-07f1-91de-9248-5f90f961bcb4 at gmail.com>,
Gordon Messmer  <centos at centos.org> wrote:
>On 06/08/2018 03:23 PM, Steve Rikli wrote:
>>
>> This seems the most likely explanation, I'd just like to know for
certain
>> before I give up on gai.conf and restort to disabling IPv6 or other
>> workarounds (e.g. /etc/nfsmount.conf).
>
>Have you tried specifying "proto=tcp" as a mount option??? That
*should*
>limit the client to IPv4.
Yes -- that's the other workaround I tried successfully.  Either in
auto.master mount options for the map, or Defaultproto=tcp in nfsmount.conf
works as desired.

I had hopes for gai.conf as the more universal solution, but apparently
it's not useable here.

Thanks,
sr.

On 06/09/2018 07:51 AM, Steve Rikli wrote:
>
> I had hopes for gai.conf as the more universal solution, but apparently
> it's not useable here.
gai.conf works as intended for most applications, here.? For example, if 
I uncomment the block of "precedence" lines, and swap between
"10" and
"100" for the last line, then "telnet www.google.com 80"
will connect to
either the IPv4 or IPv6 address based on that value.? Have you verified 
that works for you?? Do the results for that test not match the results 
for NFS mounts?

In article <05fc7f7d-897a-8a6e-f91c-f79f8aefd9c7 at gmail.com>,
Gordon Messmer  <centos at centos.org> wrote:
>On 06/09/2018 07:51 AM, Steve Rikli wrote:
>>
>> I had hopes for gai.conf as the more universal solution, but apparently
>> it's not useable here.
>
>gai.conf works as intended for most applications, here.?? For example, if 
>I uncomment the block of "precedence" lines, and swap between
"10" and
>"100" for the last line, then "telnet www.google.com 80"
will connect to
>either the IPv4 or IPv6 address based on that value.?? Have you verified 
>that works for you??? Do the results for that test not match the results 
>for NFS mounts?
That's correct -- to be clearer, gai.conf works as expected for other
things, but not what we wanted for the NFS automounter.

Thanks,
sr.