If you don’t want to have an IPv6 address on an interface, you can quickly remove it:

# ip addr show dev eth0 
2: eth0:  mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:c2:fc:59 brd ff:ff:ff:ff:ff:ff
    inet 10.210.0.141/16 brd 10.210.255.255 scope global eth0
    inet6 fe80::20c:29ff:fec2:fc59/64 scope link 
       valid_lft forever preferred_lft forever

Only get the address:

# ip addr show dev eth0 | grep inet6 | awk '{print $2}'
fe80::20c:29ff:fec2:fc59/64

Remove it:

# ip -6 addr del `ip addr show dev eth0 | grep inet6 | awk '{print $2}'` dev eth0

Or do it to many hosts:

for i in `seq 201 272`; do ssh www$i "ip -6 addr del \`ip addr show dev eth0 | grep inet6 | awk '{print \$2}'\` dev eth0"; done;