CentOS7

rpm -Uvh https://packages.microsoft.com/config/centos/7/packages-microsoft-prod.rpm
yum install dotnet-*-6.0 

# vi /etc/default/grub
      GRUB_CMDLINE_LINUX="ipv6.disable=1 rd.lvm.lv=fedora-server/root.....
# grub2-mkconfig -o /boot/grub2/grub.cfg 

# systemctl stop firewalld.service
# systemctl mask firewalld.service

# firewall-cmd --add-service=smtp --permanent
# firewall-cmd --add-service=smtp-submission --permanent
# firewall-cmd --reload 

yum install chrony
systemctl enable chronyd.service
systemctl start chronyd.service

hwclock -s --localtime

# systemctl start unit

# systemctl stop unit 

# systemctl --full 

# systemctl --full list-unit-files 

# systemctl enable unit 

# systemctl disable unit 

# systemctl daemon-reload

# systemctl kill -s 9 sshd 

# systemctl --type service