在CentOS安裝Nginx。

1. 安装Nginx

使用命令安装¹：

$ sudo dnf install nginx

安装完成后设置开机启动并启动Nginx服务：

$ sudo systemctl enable nginx.service
Created symlink /etc/systemd/system/multi-user.target.wants/nginx.service → /usr/lib/systemd/system/nginx.service.
$ sudo systemctl start nginx.service

验证Nginx是否启动成功，本地访问：

$ curl -I localhost
HTTP/1.1 200 OK
Server: nginx/...
Date: Sat, 02 May 2020 02:17:06 GMT
Content-Type: text/html
Content-Length: 4057
Last-Modified: Mon, 07 Oct 2019 21:16:24 GMT
Connection: keep-alive
ETag: "5d9bab28-fd9"
Accept-Ranges: bytes

查看当前监听的端口，可以看到80端口已经被监听：

$ netstat -lnpt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 0.0.0.0:5355            0.0.0.0:*               LISTEN      -
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      -
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      -
tcp6       0      0 :::3306                 :::*                    LISTEN      -
tcp6       0      0 :::5355                 :::*                    LISTEN      -
tcp6       0      0 :::80                   :::*                    LISTEN      -
tcp6       0      0 :::22                   :::*                    LISTEN      -

2. 设置防火墙

CentOS 7/8使用firewalld作为防火墙管理工具，查看当前防火墙状态：

$ sudo firewall-cmd --permanent --list-all
public
  target: default
  icmp-block-inversion: no
  interfaces:
  sources:
  services: cockpit dhcpv6-client ssh
  ports:
  protocols:
  masquerade: no
  forward-ports:
  source-ports:
  icmp-blocks:
  rich rules:

防火墙此时没有允许http服务，即使监听了http端口，通过Internet也是无法访问Nginx的。允许防火墙通过http服务：

$ sudo firewall-cmd --permanent --add-service=http
success

再次查看防火墙状态，出现了http服务：

$ sudo firewall-cmd --permanent --list-all
public
  target: default
  icmp-block-inversion: no
  interfaces:
  sources:
  services: cockpit dhcpv6-client http ssh
  ports:
  protocols:
  masquerade: no
  forward-ports:
  source-ports:
  icmp-blocks:
  rich rules:

刷新使防火墙更新生效：

$ sudo firewall-cmd --reload
success

此时可以通过Internet访问Nginx了，使用IP访问验证：

curl.exe -I *:80
HTTP/1.1 200 OK
Server: nginx/...
Date: Sat, 02 May 2020 02:37:49 GMT
Content-Type: text/html
Content-Length: 4057
Last-Modified: Mon, 07 Oct 2019 21:16:24 GMT
Connection: keep-alive
ETag: "5d9bab28-fd9"
Accept-Ranges: bytes

使用浏览器也可以正常访问，至此完成安装Nginx。