https://gist.github.com/shield-9/11131949 のCentOS7(iproute2)対応版

dhclient-exit-hooks

#!/bin/bash

FIRST=$(ip a show dev eth0|grep -E 'inet6 (.+) scope global'|head -n 1|sed -e "s/^ *inet6 *//g"|cut -d ":" -f1,2,3,4)
SECOND=$(ip a show dev eth0|grep -E 'inet6 (.+) scope global'|head -n 1|cut -d ":" -f5,6,7,8|cut -d "/" -f1)

if [ -z "${FIRST}" -o -z "${SECOND}" ]; then
	exit 0
fi

case "${SECOND}" in
	a[0-9]* ) exit 0
esac

IPV6=${FIRST}:a${SECOND}

for SUFFIX in `echo {0..9}`
do
	ip addr add ${IPV6}${SUFFIX}/64 dev eth0
done

for SUFFIX in `echo {a..f}`
do
	ip addr add ${IPV6}${SUFFIX}/64 dev eth0
done

exit 0

This code is in the Public Domain!