Protect your Linux server: Master these important commands

Protect your Linux server: Master these important commands

In today’s digital age, Linux servers play an increasingly important role. Whether on a personal computer or an enterprise-class server, Linux is a reliable, secure, and customizable operating system. However, security is always a critical issue. In order to protect your Linux server from potential threats, it is crucial to understand and master some important commands.

1. Firewall Rule Settings

First, you should consider setting up firewall rules to protect your server from unauthorized access. Linux provides a tool called iptables that allows you to define different rules and allow or deny specific packets. The following are several important iptables command examples:

• Enable the firewall: sudo ufw enable
• View the firewall status: sudo ufw status
• Allow inbound connections to a specific port: sudo ufw allow <port number></port>
• Allow inbound connections to a specific IP address: sudo ufw allow from <ip address></ip>

2. User Management

Controlling user access is the key to protecting the server. The following are several important commands for managing users:

• Create a new user: sudo adduser <username></username>
• Delete a user: sudo userdel &lt ;username>
• Change user password: sudo passwd <username></username>
• Add user to sudo group: sudo usermod -aG sudo &lt ;username>

3. File Permission Settings

It is critical to protect sensitive files and directories from unauthorized access. Here are some important file permission related command examples:

• Change file permissions:sudo chmod <permissions> <filename></filename></permissions>
• Change file owner ：sudo chown <username> <filename></filename></username>
• Change the group to which the file belongs: sudo chgrp <groupname> <filename></filename></groupname>

4. SSH security settings

SSH (Secure Shell) is an encrypted remote login protocol commonly used to securely access Linux servers. Here are some examples of commands that can help improve SSH security:

• Disable root login: Modify PermitRootLogin## in the /etc/ssh/sshd_config file #isno.
Disable password login: Modify
• PasswordAuthentication in the /etc/ssh/sshd_config file to no.
Restrict users allowed to log in: Add the user names allowed to log in under the
• AllowUsers line in the /etc/ssh/sshd_config file.

Log monitoring

Monitoring log files is an important means to discover potential security threats. Here are some examples of useful commands:

View system logs:
• sudo tail /var/log/syslog
View login logs:
• sudo tail /var/log/auth.log
View Apache access log:
• sudo tail /var/log/apache2/access.log

Pass By checking server logs regularly, you can spot any suspicious activity and take appropriate steps to protect it.

Summary

Protecting Linux servers is a key part of ensuring data security and network stability. By mastering the above important commands, you will be able to set firewall rules, manage users, protect files, and improve SSH security. In addition, regular monitoring of server logs is also an important means to detect potential threats in a timely manner. Remember, server security is an ongoing process and you should always be vigilant and take appropriate security measures to protect your Linux server.

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