Using CentOS 6.9 with IPv4 configured, and _not_ disabling IPv6 yet, we want this NFS client system to prefer the IPv4 address of a dual-stack remote NFS server, which has both A and AAAA records in DNS.
Otherwise we get a minutes long pause while automounter tries to mount the IPv6 address -- I can see automounter's '/bin/mount' running, using the AAAA record of the server, until that times-out and the IPv4 address of the server mounts successfully.
Disabling IPv6 altogether works around the problem as expected, but is a bigger hammer than we wanted to use. :-)
I found posts from others in a similar situation, and proposed solutions included modifying /etc/gai.conf to use:
precedence ::ffff:0:0/96 100
I cp'd /usr/share/doc/glibc-common-2.12/gai.conf to /etc/ and tried that, with several other permutations (e.g. uncommenting other blocks of "label" and "precedence" settings) but none achieved the desired effect.
Am I misunderstanding how this is supposed to work?
Cheers, sr.