Oct 232019
关闭ipv6的文章很多其实都是错误的。红帽和centos官方，其实是没正式的介绍。单独修改网卡的配置文件，删掉ipv6，是没用的。
# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 00:0c:29:bc:2c:67 brd ff:ff:ff:ff:ff:ff inet 192.168.200.10/24 brd 192.168.200.255 scope global noprefixroute ens33 valid_lft forever preferred_lft forever inet6 fe80::cb2b:20f:70fb:d627/64 scope link noprefixroute valid_lft forever preferred_lft forever
编辑 /etc/sysctl.conf
net.ipv6.conf.ens33.disable_ipv6 = 1
让修改马上生效。需要注意的是你的网卡名字，现在都已经不是eth0，ens33，我的虚拟机。
# sysctl -p net.ipv6.conf.ens33.disable_ipv6 = 1
查看一下修改的结果
# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 00:0c:29:bc:2c:67 brd ff:ff:ff:ff:ff:ff inet 192.168.200.10/24 brd 192.168.200.255 scope global noprefixroute ens33 valid_lft forever preferred_lft forever
参考文章
https://www.thegeekdiary.com/centos-rhel-7-how-to-disable-ipv6-on-a-specific-interface-only/