CentOS系统中Node.js无法连接8080端口的排查求助

我在Oracle Linux 8.7上用Node.js搭建了Web服务器，但外部无法通过8080端口访问，22端口可正常tcping通。

Node.js服务器代码 #

const http = require('http');
const hostname = '0.0.0.0';
const port = '8080';

httpd = http.createServer(function (req, res) {
    res.writeHead(200, {'Content-Type': 'text/html'});
    res.end('Hello World!');
});

httpd.listen(port, hostname, function(){
    console.log('Server Start');
});

tcping测试结果 #

C:\Users\user>tcping -p 22 <centOS IP>
Probing <centOS IP>:22/tcp - Port is open - time=14.019ms
Probing <centOS IP>:22/tcp - Port is open - time=13.159ms
Probing <centOS IP>:22/tcp - Port is open - time=8.601ms
Probing <centOS IP>:22/tcp - Port is open - time=9.896ms

C:\Users\user>tcping -p 8080 <centOS IP>
Probing <centOS IP>:8080/tcp - No response - time=2010.980ms
Probing <centOS IP>:8080/tcp - No response - time=2008.277ms
Probing <centOS IP>:8080/tcp - No response - time=2008.509ms
Probing <centOS IP>:8080/tcp - No response - time=2000.949ms

已完成的检查 #

• 确认8080端口处于监听状态（netstat输出显示0.0.0.0:8080处于LISTEN状态）
• 已关闭系统层面防火墙：firewalld处于masked/inactive状态，iptables服务未安装，nftables处于inactive状态

相关命令输出 #

[opc@instance-20220607-1056 webTest]$ netstat -tnlp
(Not all processes could be identified, non-owned process info
will not be shown, you would have to be root to see it all.)
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 127.0.0.1:9003          0.0.0.0:*               LISTEN      -
tcp        0      0 0.0.0.0:111             0.0.0.0:*               LISTEN      -
tcp        0      0 0.0.0.0:8080            0.0.0.0:*               LISTEN      -
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN
.
.

[opc@instance-20220607-1056 webTest]$ sudo service iptables status
Redirecting to /bin/systemctl status iptables.service
Unit iptables.service could not be found.

[opc@instance-20220607-1056 webTest]$ sudo systemctl status nftables
nftables.service - Netfilter Tables
Loaded: loaded (/usr/lib/systemd/system/nftables.service; disabled; vendor p>
Active: inactive (dead)
Docs: man:nft(8)
lines 1-4/4 (END)

[opc@instance-20220607-1056 webTest]$ sudo systemctl status firewalld
firewalld.service
Loaded: masked (Reason: Unit firewalld.service is masked.)
Active: inactive (dead)

Jan 05 17:49:52 instance-20220607-1056 systemd[1]: Starting firewalld - dynamic firewall daemon...
Jan 05 17:49:54 instance-20220607-1056 systemd[1]: Started firewalld - dynamic firewall daemon.
Jan 05 17:49:54 instance-20220607-1056 firewalld[1480]: WARNING: AllowZoneDrifting is enabled. This is consi>
Jan 05 20:38:06 instance-20220607-1056 systemd[1]: Stopping firewalld - dynamic firewall daemon...
Jan 05 20:38:10 instance-20220607-1056 systemd[1]: firewalld.service: Succeeded.
Jan 05 20:38:10 instance-20220607-1056 systemd[1]: Stopped firewalld - dynamic firewall daemon.

[opc@instance-20220607-1056 webTest]$ sudo lsb_release -a
LSB Version:    :core-4.1-amd64:core-4.1-noarch
Distributor ID: OracleServer
Description:    Oracle Linux Server release 8.7
Release:        8.7
Codename:       n/a

还需要检查的内容 #

• 本地验证服务可用性：在服务器上执行curl http://localhost:8080或telnet localhost 8080，确认服务本身是否能正常响应。如果本地也无法访问，需检查Node进程是否正常运行，或代码是否存在问题（比如httpd未声明为局部变量，建议添加let/const避免全局变量异常）。
• 云服务器安全组规则：如果是云服务商提供的服务器（如Oracle Cloud），需确认安全组是否允许外部IP访问8080端口的TCP流量。云安全组独立于系统防火墙，即使系统防火墙关闭，安全组拦截也会导致无法访问。
• SELinux状态检查：Oracle Linux默认启用SELinux，执行sestatus查看状态，若为Enforcing模式，可能阻止Node.js绑定端口或对外提供服务。可临时执行sudo setenforce 0关闭SELinux测试，若能正常访问，再配置SELinux规则允许Node.js的网络权限。
• 端口监听进程验证：执行sudo netstat -tnlp | grep 8080获取监听端口的PID，再用ps -p <PID>确认该进程是否为Node.js。若不是，说明端口被其他程序占用，需更换端口或停止占用进程。
• 网络路由与NAT设置：确认服务器是否拥有正确的公网IP，若通过NAT网关访问公网，需检查网关是否配置了8080端口的转发规则。
• Node.js服务日志排查：用ps aux | grep node确认Node进程是否存在，若进程异常退出，检查启动命令是否有错误，或使用守护进程（如pm2）时是否配置正确。

内容的提问来源于stack exchange，提问作者Jinhee Lee