Learn to use command line tools: key skills to improve server security

Learn to use command line tools: key skills to improve server security

In the current information age, server security cannot be ignored. As a server administrator or operator, it is particularly important to have the knowledge and skills to use command line tools to improve server security. This article will introduce some commonly used command line tools and their applications to help readers strengthen server security.

1. SSH (Secure Shell)

SSH is an encryption protocol for remote login through the Internet. It uses a combination of public and private keys to connect more securely. to the server. Using SSH, you can protect the security of transmitted data and prevent it from being intercepted and tampered by middlemen. The following is a sample code for using SSH to connect to the server:

ssh username@server_IP

where username is your username on the server, and server_IP is the IP address of the server.

2. File permission management

On the server, it is very important to correctly set the permissions of files and directories. The chmod command can change the permissions of a file or directory. The most commonly used parameters are , - and =. Here are some common examples:

# 添加某一权限
chmod +x filename

# 取消某一权限
chmod -r filename

# 只保留某一权限
chmod =rwx filename

3. Firewall

Firewalls can help protect servers from network attacks. iptables is a commonly used command line tool for configuring firewall rules on Linux systems. Here are some common usage examples:

# 启用防火墙
sudo iptables -F

# 开放指定端口
sudo iptables -A INPUT -p tcp --dport 80 -j ACCEPT

# 拒绝指定IP访问
sudo iptables -A INPUT -s IP_address -j DROP

4. System log monitoring

System logs are an important source of server information. The tail command can be used to monitor changes in log files in real time, and regular viewing can help detect abnormalities. The following is an example:

# 查看最新的若干行日志
tail -n 100 log_file

# 实时监控日志文件
tail -f log_file

5. Intrusion Detection

Intrusion Detection System (IDS) can detect and prevent intrusions by monitoring network traffic and system logs . snort is a commonly used open source IDS tool that can be used to monitor network traffic in real time. The following is an example of using snort for rule-based intrusion detection:

# 启动snort
sudo snort -A console -q -c /etc/snort/snort.conf

# 在运行中加载新规则
sudo snort -R rules_file

The above are just some examples of command line tools. By flexibly using these tools, the security of the server can be improved. In addition, you should also maintain continuous learning about network security, understand the latest security threats and attack technologies, and take corresponding protective measures in a timely manner.

In short, mastering the use of command line tools is a key skill to improve server security. This article introduces some common tools and their applications, and provides corresponding code examples. Through learning and practice, readers can continuously improve their server security and reduce the risk of attacks.

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