Ubuntu20.04下Nginx安装Certbot后出现ERR_TOO_MANY_REDIRECTS错误求助

之前一直使用Apache，刚切换到Nginx，按教程安装Nginx并配置Let's Encrypt SSL证书，初期可正常使用，之后出现**ERR_TOO_MANY_REDIRECTS（重定向次数过多）**错误，以下是相关配置及修复方案：

配置文件详情 #

/var/www/sites-available/my_domain #

server {
        root /var/www/my_domain/html;
        index index.html index.htm index.nginx-debian.html;

        server_name my_domain;

        location / {
                rewrite ^(/.*)\.html(\?.*)?$ $1$2 permanent;
                rewrite ^/(.*)/$ /$1 permanent;
                try_files $uri/index.html $uri.html $uri/ $uri =404;
        }

    listen [::]:443 ssl ipv6only=on; # managed by Certbot
    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/my_domain/fullchain.pem; # managed by Certbot    
    ssl_certificate_key /etc/letsencrypt/live/my_domain/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

}
server {
    if ($host = my_domain) {
        return 301 https://$host$request_uri;
    } # managed by Certbot

        listen 80;
        listen [::]:80;

        server_name my_domain;
    return 404; # managed by Certbot

}

/var/www/sites-enabled/my_domain #

server {
        root /var/www/my_domain/html;
        index index.html index.htm index.nginx-debian.html;

        server_name my_domain;

        location / {
                rewrite ^(/.*)\.html(\?.*)?$ $1$2 permanent;
                rewrite ^/(.*)/$ /$1 permanent;
                try_files $uri/index.html $uri.html $uri/ $uri =404;
        }

    listen [::]:443 ssl ipv6only=on; # managed by Certbot
    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/my_domain/fullchain.pem; # managed by Certbot    
    ssl_certificate_key /etc/letsencrypt/live/my_domain/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

}
server {
    if ($host = my_domain) {
        return 301 https://$host$request_uri;
    } # managed by Certbot

        listen 80;
        listen [::]:80;

        server_name my_domain;
    return 404; # managed by Certbot

}

UFW防火墙设置 #

Status: active

To                         Action      From
--                         ------      ----
22/tcp                     ALLOW       Anywhere                  
22                         ALLOW       Anywhere                  
Nginx Full                 ALLOW       Anywhere                  
22/tcp (v6)                ALLOW       Anywhere (v6)             
22 (v6)                    ALLOW       Anywhere (v6)             
Nginx Full (v6)            ALLOW       Anywhere (v6)

Cloudflare配置说明 #

使用Cloudflare作为DNS服务，SSL/TLS模式设置为完全（严格）。

问题现象 #

配置初期SSL可正常工作，之后浏览器提示ERR_TOO_MANY_REDIRECTS（重定向次数过多），无法访问网站。

修复方案 #

核心原因 #

Cloudflare完全（严格）模式要求源服务器必须通过HTTPS通信，但当前Nginx配置会把Cloudflare转发的HTTP请求重定向到HTTPS，形成循环：Cloudflare发HTTP请求→Nginx重定向到HTTPS→Cloudflare再次转发→Nginx再次重定向。

具体步骤 #

1. 临时验证问题根源：将Cloudflare SSL/TLS模式改为灵活，测试是否消除重定向循环。

2. 修改Nginx 80端口配置：
   替换原80端口的server块内容，通过Cloudflare传递的X-Forwarded-Proto头判断用户原始请求协议，仅当原始请求为HTTP时才重定向到HTTPS：

   server {
       listen 80;
       listen [::]:80;
       server_name my_domain;
   
       # 仅对用户原始HTTP请求重定向到HTTPS
       if ($http_x_forwarded_proto = "http") {
           return 301 https://$host$request_uri;
       }
   
       # 保留Certbot续期所需的ACME挑战路径
       location /.well-known/acme-challenge/ {
           root /var/www/my_domain/html;
           allow all;
       }
   
       return 404;
   }
   

3. 验证配置并重启Nginx：

   • 检查配置语法：sudo nginx -t
   • 重启服务：sudo systemctl reload nginx

4. 恢复Cloudflare模式：确认Nginx配置生效后，将Cloudflare SSL/TLS模式改回完全（严格）。

内容的提问来源于stack exchange，提问作者Monkee_coder