以Debian为例，配置多IP和IPv6

vi /etc/network/interfaces
auto lo
 iface lo inet loopback

auto enp3
 iface enp3 inet static
  address 192.187.88.21/29
  gateway 192.187.88.20
  dns-nameservers 8.8.8.8 8.8.4.4

auto enp3:0
 iface enp3:0 inet static
  address 192.187.88.22/29

auto enp3:1
 iface enp3:1 inet static
  address 192.187.88.23/29

auto enp3:2
 iface enp3:2 inet static
  address 192.187.88.24/29

auto enp3:3
 iface enp3:3 inet static
  address 192.187.88.25/29

 iface enp3 inet6 static
  address 2604:2048:a:12a::2/64
  gateway 2604:2048:a:12a::1
  up ip addr add 2604:2048:a:12a::1024/64 dev enp3
  up ip addr add 2604:2048:a:12a::1025/64 dev enp3

注意网卡名和网关。如上，IPv6可以配置很多，很多个。
最后重启一下网络服务：

systemctl restart networking