Protect your Linux server: Become proficient with these commands

Protect your Linux server: Use these commands proficiently

With the development of cloud computing and network technology, Linux servers are becoming more and more popular among enterprises and individual users . As a stable and reliable operating system, Linux provides many powerful security features to protect servers from threats of intrusion and data leakage. However, in order to better protect your Linux server, it is necessary to understand and apply some important commands. In this article, we will introduce some proficient commands to strengthen the security of your Linux server.

1. iptables: iptables is a powerful firewall tool that controls network traffic by configuring rules. Proficient use of iptables allows you to limit unnecessary access and protect your server from network attacks. Commonly used commands are:

• iptables -L: View the current firewall rules.
• iptables -A INPUT -p tcp --dport 22 -j DROP: Use this command to block all access to the SSH port.

2. fail2ban: fail2ban is a tool used to prevent brute force attacks. It monitors the server's log files and blocks access from malicious IP addresses based on set rules. Proficient use of fail2ban can greatly reduce the impact of brute force attacks on the server. Commonly used commands are:

• fail2ban-client status: Check the status of fail2ban.
• fail2ban-client set ssh banip 10.0.0.1: Use this command to add the IP address 10.0.0.1 to the SSH ban list.

3. chown and chmod: chown and chmod are commands used to set file permissions and owners. Properly setting file owners and permissions can prevent unauthorized users from accessing sensitive files. Commonly used commands are:

• chown root:root /path/to/file: Set the owner of the file to the root user.
• chmod 700 /path/to/file: Set the file permissions so that only the owner can read, write, and execute.

4. ssh-keygen: ssh-keygen is a command used to generate and manage SSH key pairs. Using an SSH key pair provides more secure remote access and prevents unauthorized users from logging in with passwords. Commonly used commands are:

• ssh-keygen -t rsa: Generate an RSA key pair for authentication.
• ssh-copy-id user@server: Copy the public key to the remote server to achieve password-free login.

5. Sudo: Sudo is a tool used to authorize ordinary users to execute privileged commands. Using Sudo can limit the use of privileged commands and reduce the risk of attacks by malicious code on your system. Commonly used commands are:

• sudo apt-get update: Use Sudo to execute privileged commands.

6. SELinux and AppArmor: SELinux and AppArmor are two mandatory access control tools used to harden Linux security. They reduce potential security vulnerabilities by enforcing which processes can access system resources. Commonly used commands are:

• getenforce: Check the status of SELinux.
• aa-status: View the status of AppArmor.

It is very important to be proficient in using these commands when protecting your Linux server. They can help you build stronger firewalls, block brute force attacks, restrict file access, use secure remote access methods, and harden operating system security. However, be careful when using these commands to avoid accidentally affecting the normal operation of the server.

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