IPv6 is enabled by default. Stateless address autoconfiguration is used to automatically assign IPv6 addresses to all interfaces. You can disable IPv6 support globally by setting: networking.enableIPv6 = false; You can disable IPv6 on a single interface using a normal sysctl (in this example, we use interface eth0): boot.kernel.sysctl."net.ipv6.conf.eth0.disable_ipv6" = true; As with IPv4 networking interfaces are automatically configured via DHCPv6. You can configure an interface manually: networking.interfaces.eth0.ip6 = [ { address = "fe00:aa:bb:cc::2"; prefixLength = 64; } ]; For configuring a gateway, optionally with explicitly specified interface: networking.defaultGateway6 = { address = "fe00::1"; interface = "enp0s3"; } See for similar examples and additional information.