ipv6 disable
/etc/sysctrl.conf
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1
net.ipv6.conf.NETWORKINTERFACENAME.disable_ipv6 = 1
sysctl -p
cat /proc/sys/net/ipv6/conf/*/disable_ipv6
/etc/default/grub
GRUB_CMDLINE_LINUX="xxxxx ipv6.disable=1"
update-grub
ipv4
/etc/network/interfaces
auto enp35s0
iface enp35s0 inet static
address 116.202.112.180
netmask 255.255.255.192
gateway 116.202.112.129
# route 116.202.112.128/26 via 116.202.112.129
up route add -net 116.202.112.128 netmask 255.255.255.192 gw 116.202.112.129 dev enp35s0