来自http://tunps.com/turn_off_ipv6_in_linux
禁止 ipv6：
修改 /etc/modprobe.d/aliases
注释 alias net-pf-10 ipv6
下面加一行 alias net-pf-10 off
重启后就没了
为什么要这样改呢？
# network protocols ##########################################################
alias net-pf-1 unix
alias net-pf-2 ipv4
alias net-pf-3 ax25
alias net-pf-4 ipx
alias net-pf-5 appletalk
alias net-pf-6 netrom
alias net-pf-7 bridge
alias net-pf-8 atm
alias net-pf-9 x25
alias net-pf-10 ipv6
alias net-pf-11 rose
alias net-pf-12 decnet
# 13 NETBEUI
alias net-pf-15 af_key
alias net-pf-16 af_netlink
alias net-pf-17 af_packet
# 18 ASH
alias net-pf-19 af_econet
alias net-pf-20 atm
# 22 SNA
alias net-pf-23 irda
alias net-pf-24 pppoe
alias net-pf-25 wanrouter
alias net-pf-26 llc
alias net-pf-31 bluetooth
alias net-pf-16-proto-1 wire
alias net-pf-16-proto-3 ip_queue
alias net-pf-16-proto-4 tcp_diag
alias net-pf-16-proto-8 scsi_transport_iscsi
alias net-pf-16-proto-9 audit
alias net-pf-16-proto-11 cn
alias net-pf-16-proto-13 ip6_queue
# network protocols ##########################################################
alias net-pf-1 unix
alias net-pf-2 ipv4
alias net-pf-3 ax25
alias net-pf-4 ipx
alias net-pf-5 appletalk
alias net-pf-6 netrom
alias net-pf-7 bridge
alias net-pf-8 atm
alias net-pf-9 x25
alias net-pf-10 ipv6
alias net-pf-11 rose
alias net-pf-12 decnet
# 13 NETBEUI
alias net-pf-15 af_key
alias net-pf-16 af_netlink
alias net-pf-17 af_packet
# 18 ASH
alias net-pf-19 af_econet
alias net-pf-20 atm
# 22 SNA
alias net-pf-23 irda
alias net-pf-24 pppoe
alias net-pf-25 wanrouter
alias net-pf-26 llc
alias net-pf-31 bluetooth
alias net-pf-16-proto-1 wire
alias net-pf-16-proto-3 ip_queue
alias net-pf-16-proto-4 tcp_diag
alias net-pf-16-proto-8 scsi_transport_iscsi
alias net-pf-16-proto-9 audit
alias net-pf-16-proto-11 cn
alias net-pf-16-proto-13 ip6_queue
每个贷后都跟有其网络类型，alias net-pf-10也就是 ipv6的网络“代号”了，#使它变成注释而无效，加个off来禁用。
