firewalld--centos7.x firewall--use process steps:

How to use firewalld correctly:
1: Default zone

• 1.>Learn to view the default zone
• 2.>Set the default zone
• 3.> The rules of the default zone should be set carefully. If there is no match in the services of other zones, it will go to the default zone to match. If the default zone is not available, it will be rejected.

2: Associate traffic with zone 1> Associate zone
with source IP

1. View/remove/add/change

2>Associate zone through network card

3: Set basic rules and rich rules in the zone

1. 1>Add permanent rules
2. 2>Service name adding rules
3. 3>Add rules by port
4. 4>View rules/remove rules