查看linux ssh端口-查看linux ssh端口

SSH（Secure Shell）是用于远程登录和管理服务器的加密协议，广泛应用于Linux系统中。查看SSH端口是确保系统安全性和访问控制的重要环节。SSH端口通常为22，但有时可能被修改或使用其他端口，如2222、2233等。在实际运维和安全审计中，了解SSH端口的使用情况有助于识别潜在的安全风险、管理远程访问权限以及排查服务配置问题。本文将详细阐述如何在Linux系统中查看SSH端口，包括使用命令行工具、查看系统配置文件、使用网络工具等方法，帮助用户全面掌握SSH端口的管理与监控技巧。
一、SSH端口的基本概念 SSH端口是用于建立加密连接的网络端口，通常为22。它是Linux系统中用于远程登录和管理服务器的默认端口。SSH协议通过加密传输数据，确保用户在远程访问时的信息安全。在实际应用中，用户可能需要通过SSH连接到服务器，因此了解SSH端口的使用情况至关重要。
二、查看SSH端口的常用方法
1.使用`netstat`命令查看监听端口 `netstat` 是一个用于查看网络连接状态的命令行工具。通过该命令，用户可以查看当前系统上所有监听的端口，包括SSH端口。 命令示例： ```bash sudo netstat -tuln | grep :22 ``` 解释： - `-t`：显示TCP连接 - `-u`：显示UDP连接 - `-l`：显示监听中的端口 - `-n`：显示数字形式的地址和端口 输出示例： ``` tcp6 0 0 :22 : LISTEN ``` 该命令将显示SSH端口是否正在监听，若显示“LISTEN”则表示SSH服务正在运行。
2.使用`ss`命令查看监听端口 `ss` 是 `netstat` 的替代工具，功能相似，但更高效。它也可以用来查看监听端口。 命令示例： ```bash sudo ss -tuln | grep :22 ``` 输出示例： ``` tcp LISTEN 0 128 :22 : ``` 该命令同样可以确认SSH端口是否处于监听状态。
3.使用`lsof`命令查看进程和端口 `lsof` 是一个用于查找打开文件和网络连接的命令行工具。它可以帮助用户查看哪些进程正在使用SSH端口。 命令示例： ```bash sudo lsof -i -P -n | grep :22 ``` 输出示例： ``` COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME sshd 1234 root 6u IPv4 12345 0t0 TCP :22 (LISTEN) ``` 该命令显示进程 `sshd`（SSH服务）正在监听22端口。
4.使用`firewalld`或`iptables`查看端口规则 在某些Linux发行版中，防火墙规则可能限制了SSH端口的访问。使用 `firewalld` 或 `iptables` 可以查看端口规则，确认SSH端口是否被允许。 使用 `firewalld` 示例： ```bash sudo firewall-cmd --list-all | grep :22 ``` 使用 `iptables` 示例： ```bash sudo iptables -L -n -v | grep :22 ``` 输出示例： ``` tcp 10000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 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