[CentOS] firewalld and LISTEN

[Gordon Messmer]

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.