On 07/27/2017 06:36 PM, 望月忠雄 wrote: > But by ss -nat, IPV4 443 is not listend. How can I fix? > > # ss -nat | grep LISTEN | grep 443 > LISTEN 0 128 :::443 :::* By default, Linux processes that listen on an IPv6 port will also listen on the IPv4 port (when no specific address is specified): http://man7.org/linux/man-pages/man7/ipv6.7.html You could change that behavior by modifying /proc/sys/net/ipv6/bindv6only, but your system is working normally now.