To improve network efficiency disable IPv6 if you really do not need it:
* add NETWORKING_IPV6=no in /etc/sysconfig/network file.
{{{
#!div style="font-size: 90%"
{{{#!sh
echo NETWORKING_IPV6=no >> /etc/sysconfig/network
}}}
}}}
* disable the ipv6 option in the kernel
make *.conf file (e.g. ipv6.conf) ) under /etc/modprobe.d/ directory and add “options ipv6 disable=1”
{{{
#!div style="font-size: 90%"
{{{#!sh
echo options ipv6 disable=1 > /etc/modprobe.d/ipv6.conf
}}}
}}}

'''IMPORTANT:''' Reboot machine to introduce changes into life.