LinuxQuestions.org - can't mount an nfs share when i disable ipv6 in sysctl in rhel7.3

why am i un able to mount an NFS share if i disable IPv6 in rhel7.3?

error:

Code:

# systemctl status rpc-statd.service

● rpc-statd.service - NFS status monitor for NFSv2/3 locking.

  Loaded: loaded (/usr/lib/systemd/system/rpc-statd.service; static; vendor preset: disabled)

  Active: failed (Result: exit-code) since Tue 2017-11-28 10:05:44 GST; 8min ago

  Process: 34683 ExecStart=/usr/sbin/rpc.statd --no-notify $STATDARGS (code=exited, status=1/FAILURE)



Nov 28 10:05:44 servername rpc.statd[34684]: Flags: TI-RPC

Nov 28 10:05:44 servername rpc.statd[34684]: Failed to register (statd, 1, udp): svc_reg() err: RPC: Remote system error - No route to host

Nov 28 10:05:44 servername rpc.statd[34684]: Failed to register (statd, 1, tcp): svc_reg() err: RPC: Remote system error - No route to host

Nov 28 10:05:44 servername rpc.statd[34684]: Failed to register (statd, 1, udp6): svc_reg() err: RPC: Remote system error - No route to host

Nov 28 10:05:44 servername rpc.statd[34684]: Failed to register (statd, 1, tcp6): svc_reg() err: RPC: Remote system error - No route to host

Nov 28 10:05:44 servername rpc.statd[34684]: failed to create RPC listeners, exiting

Nov 28 10:05:44 servername systemd[1]: rpc-statd.service: control process exited, code=exited status=1

Nov 28 10:05:44 servername systemd[1]: Failed to start NFS status monitor for NFSv2/3 locking..

Nov 28 10:05:44 servername systemd[1]: Unit rpc-statd.service entered failed state.

Nov 28 10:05:44 servername systemd[1]: rpc-statd.service failed.

the changes are in /etc/sysctl.conf:

Code:

#disable IPv6

net.ipv6.conf.all.disable_ipv6 = 1

net.ipv6.conf.default.disable_ipv6 = 1

i can mount nfs if i remove the 2 lines in sysctl.conf and restart the server.