In-depth understanding of Linux server security: application and maintenance of commands

In-depth understanding of Linux server security: command application and maintenance

With the development of the Internet, the security of Linux servers is particularly critical. Protecting servers from malicious attacks and illegal intrusions is critical to maintaining the normal operation of the system. This article will introduce some commonly used Linux commands and their application in server security maintenance. By in-depth understanding of these commands, we can better protect our servers.

1. Firewall configuration

The firewall is the first line of defense to protect the server. By restricting network traffic, it prevents illegal access and malicious attacks. Firewall rules can be configured using the following command:

iptables -A INPUT -p tcp --dport 22 -j DROP
iptables -A INPUT -p tcp --dport 80 -j ACCEPT
iptables - A INPUT -p tcp --dport 443 -j ACCEPT

In this example, we turn off SSH (port 22) access through the iptables command, and then allow HTTP (port 80) and HTTPS (port 443) Access. This prevents unauthorized users from accessing the server.

2. User rights management

Correct management of user rights is also one of the important measures to protect the server. The following are common commands for managing users and groups:

User management:

• Create user: useradd username
• Delete user: userdel username
• Change password: passwd username
• View user list: cat /etc/passwd

Group management:

• Create group: groupadd groupname
• Delete group: groupdel groupname
• Add user to group: usermod -a -G groupname username
• View group list: cat /etc/group

With appropriate user and group management, access to server resources can be restricted.

3. File permission settings

File permissions are one of the important measures to protect server data. The following are common commands for managing file permissions:

• Change the owner of a file: chown username filename
• Change the group to which a file belongs: chgrp groupname filename
• Change a file Permissions: chmod permissions filename

Use these commands to ensure that only authorized users can access and modify critical files.

4. Logging and auditing

Logging and auditing are important means of identifying and tracking potential attacks. The following are common commands for managing logging and auditing:

• View the system log: tail -f /var/log/syslog
• View the login log: tail -f /var /log/auth.log
• View user activity log: last username

By regularly checking these log files, we can quickly discover potential security risks and take appropriate measures.

5. Encryption and SSL Certificate

In order to protect the data transmission between the server and the user, encryption and SSL certificate play a key role. The following are common commands for managing encryption and SSL certificates:

• Generate an SSL certificate: openssl req -new -x509 -days 365 -nodes -out server.crt -keyout server.key
• Install SSL certificate: cp server.crt /etc/apache2/ssl.crt/
• Modify the Apache configuration file to enable SSL: vi /etc/apache2/sites-available/default-ssl.conf

By properly configuring and managing SSL certificates, you can ensure that data transmission between the server and the client is secure.

Summary:

The maintenance of Linux server security is inseparable from the use of commands. This article introduces some common commands and gives usage examples. By having a deep understanding of what these commands do and how to use them, we can better protect our servers. Of course, this is only one aspect of server security. In addition to command line tools, there are many other security measures and technologies that need to be applied comprehensively. In the process of protecting server security, we should continue to learn and master new knowledge to deal with ever-changing security threats.

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