Récemment, divers services prennent en charge IPv4 et IPv6. Limitons ces services à IPv4 uniquement cette fois.
Apache(http)
/etc/httpd/conf/httpd.conf
#Listen 80
Listen 0.0.0.0:80
Apache(https)
/etc/httpd/conf.d/ssl.conf
#Listen 443 https
Listen 0.0.0.0:443 https
ssh
/etc/ssh/sshd_config
#AddressFamily any
AddressFamily inet
MySQL(v8)
/etc/my.cnf.d/mysql-server.cnf
[mysqld]
bind-address=127.0.0.1
mysqlx-bind-address = 127.0.0.1
PostgreSQL
pg_hba.conf
#host all all ::1/128 trust
host all all 127.0.0.1 255.255.255.255 trust