linux 查看所有端口占用-查看端口占用

在现代IT系统中，Linux 系统的稳定运行依赖于对端口占用的合理管理。端口是网络通信的核心，用于进程间的数据交换。
也是因为这些，查看所有端口占用成为系统监控、安全审计和性能优化的重要环节。本文将详细介绍在 Linux 系统中如何高效地查看所有端口占用情况，涵盖命令行工具、脚本编写、系统日志分析以及实际应用场景，帮助读者全面掌握这一技能。
一、Linux 系统端口管理的基础知识 在 Linux 系统中，端口通常使用 TCP/IP 协议进行通信。每个端口有唯一的 端口号（范围从 0 到 65535），并由 进程 使用来监听或发送数据。端口占用的检测有助于识别潜在的资源冲突、服务异常或安全威胁。
1.1端口分类 - 系统端口：由系统预留，如 21（FTP）、22（SSH）、80（HTTP）等。 - 应用程序端口：由特定应用程序占用，如 3000（Node.js）、443（HTTPS）等。 - 临时端口：用于临时通信，通常在 49152 到 65535 之间。
1.2端口占用的检测方法 端口占用的检测可以通过以下方式实现： - netstat：实时监控网络连接状态。 - ss：更现代、性能更优的工具。 - lsof：列出打开的文件和进程。 - grep：用于筛选特定端口的信息。
二、使用 netstat 查看所有端口占用
2.1基础用法 `netstat` 是一个传统工具，用于显示网络连接状态。基本命令如下： ```bash sudo netstat -tuln ``` - `-t`：显示 TCP 连接。 - `-u`：显示 UDP 连接。 - `-l`：仅显示监听中的端口。 - `-n`：以数字形式显示端口，不解析主机名。
2.2详细输出解析 输出示例： ``` Active Internet connections (servers and peers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Name tcp6 0 0 127.0.0.1:6379 0.0.0.0: LISTEN 1234/redis tcp6 0 0 0.0.0.0:22 0.0.0.0: LISTEN 5678/ssh tcp6 0 0 0.0.0.0:80 0.0.0.0: LISTEN 9876/httpd ``` - Proto：协议类型。 - Recv-Q：接收队列大小。 - Send-Q：发送队列大小。 - Local Address：本地地址和端口。 - Foreign Address：远程地址和端口。 - State：连接状态。 - PID/Name：进程 ID 和名称。
2.3指定端口查看 若需查看特定端口，可使用如下命令： ```bash sudo netstat -tuln | grep :80 ``` 或使用 `grep` 进行筛选： ```bash sudo netstat -tuln | grep :80 ```
三、使用 ss 命令查看端口占用 `ss` 是 `netstat` 的现代替代工具，性能更高，支持更丰富的选项。
1.1基础用法 ```bash sudo ss -tuln ``` - `-t`：显示 TCP 连接。 - `-u`：显示 UDP 连接。 - `-l`：显示监听中的端口。 - `-n`：不解析主机名，直接显示端口号。
3.2详细输出解析 输出示例： ``` Active Internet connections (servers and peers) Proto State Local Address:Port Peer Address:Port PID/Name tcp LISTEN 0.0.0.0:22 0.0.0.0: 5678/ssh tcp LISTEN 0.0.0.0:80 0.0.0.0: 9876/httpd tcp LISTEN [::]:22 [::]: 5678/ssh ``` - Proto：协议类型。 - State：连接状态。 - Local Address：本地地址和端口。 - Peer Address：远程地址和端口。 - PID/Name：进程 ID 和名称。
3.3指定端口查看 ```bash sudo ss -tuln | grep :80 ```
四、使用 lsof 查看端口占用 `lsof` 是一个强大的工具，用于列出所有打开的文件和进程，包括端口占用。
4.1基础用法 ```bash sudo lsof -i -P -n ``` - `-i`：显示网络连接。 - `-P`：不解析协议和端口。 - `-n`：不解析主机名。
4.2详细输出解析 输出示例： ``` COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME nginx 1234 root 4u IPv4 12345 0t0 TCP :80 (LISTEN) sshd 5678 root 3u IPv4 56789 0t0 TCP :22 (LISTEN) ``` - COMMAND：进程名称。 - PID：进程 ID。 - USER：用户。 - FD：文件描述符。 - TYPE：文件类型（如 IPv4、IPv6）。 - DEVICE：设备号。 - SIZE/OFF：大小和偏移。 - NODE NAME：名称（如 `:80`）。
4.3指定端口查看 ```bash sudo lsof -i -P -n | grep :80 ```
五、使用 grep 进行端口筛选 在以上命令中，`grep` 可用于快速筛选特定端口。
5.1基础用法 ```bash sudo netstat -tuln | grep :80 ```
5.2多端口筛选 ```bash sudo netstat -tuln | grep -E '80|22|443' ``` - -E：启用正则表达式匹配。
六、使用脚本自动化查看端口占用 在实际环境中，脚本可以用于自动化监控和报告端口占用情况。 6.1 使用 bash 脚本 ```bash !/bin/bash 查看所有监听端口 echo "Listening ports:" sudo netstat -tuln | grep :80 | awk '{print $4, $5}' sudo netstat -tuln | grep :22 | awk '{print $4, $5}' sudo netstat -tuln | grep :443 | awk '{print $4, $5}' ``` 6.2 使用 Python 脚本 ```python import subprocess def get_listening_ports(): result = subprocess.run( ['sudo', 'netstat', '-tuln'], capture_output=True, text=True ) return result.stdout print(get_listening_ports()) ```
七、系统日志分析端口占用 在 Linux 系统中，日志文件（如 `/var/log/messages`、`/var/log/syslog`）可以提供端口占用的详细信息。 7.1 日志文件分析 ```bash sudo tail -n 100 /var/log/messages | grep -E 'tcp|udp|listen' ``` - tcp：显示 TCP 连接。 - udp：显示 UDP 连接。 - listen：显示监听中的端口。 7.2 日志解析示例 ``` Mar 15 10:00:00 host1 kernel: [12345] type=1300 audit(1677721600:1): msg=10000003 audit_type=0:0 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