Nginx反向代理ASP.Net应用失效，请求排查配置问题

问题描述 #

我有4个ASP.Net应用，尝试通过Nginx反向代理对外提供服务，但始终无法正常访问。无论调整何种配置都无法解决问题，急需帮助排查错误。

Nginx.conf配置 #

user nginx;
worker_processes auto;

error_log /var/log/nginx/error.log notice;
pid /var/run/nginx.pid;

events {
    worker_connections 1024;
}

http {
    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    log_format main '$remote_addr - $remote_user [$time_local] "$request" '
                    '$status $body_bytes_sent "$http_referer" '
                    '"$http_user_agent" "$http_x_forwarded_for"';

    access_log /var/log/nginx/access.log main;

    sendfile on;
    keepalive_timeout 65;

   server {
       listen 80 default_server;
       listen [::]:80 default_server;

        location / {
            root   /usr/share/nginx/html;
            index  index.html index.htm;
        }

       location /auth {
           proxy_pass http://0.0.0.0:5160;
           proxy_http_version 1.0;
           proxy_set_header Upgrade $http_upgrade;
           proxy_set_header Connection keep-alive;
           proxy_set_header Host $host;
           proxy_cache_bypass $http_upgrade;
           proxy_intercept_errors on;
       }

       location /company {
           proxy_pass http://0.0.0.0:5287;
           proxy_http_version 1.0;
           proxy_set_header Upgrade $http_upgrade;
           proxy_set_header Connection keep-alive;
           proxy_set_header Host $host;
           proxy_cache_bypass $http_upgrade;
           proxy_intercept_errors on;
       }

       location /equipment {
           proxy_pass http://0.0.0.0:5176;
           proxy_http_version 1.0;
           proxy_set_header Upgrade $http_upgrade;
           proxy_set_header Connection keep-alive;
           proxy_set_header Host $host;
           proxy_cache_bypass $http_upgrade;
           proxy_intercept_errors on;
       }

       location /featureflags {
           proxy_pass http://0.0.0.0:5291;
           proxy_http_version 1.0;
           proxy_set_header Upgrade $http_upgrade;
           proxy_set_header Connection keep-alive;
           proxy_set_header Host $host;
           proxy_cache_bypass $http_upgrade;
           proxy_intercept_errors on;
       }

       error_page   500 502 503 504  /50x.html;
       location = /50x.html {
           root   /usr/share/nginx/html;
       }

       error_page 400 401 402 403 404 /40x.html;
       location = /40x.html {
           root /usr/share/nginx/html;
       }
   }
}

应用健康检查地址 #

• http://localhost:5160/api/health/healthCheck --> Authentication
• http://localhost:5291/api/health/healthCheck --> FeatureFlags
• http://localhost:5176/api/health/healthCheck --> Equipment
• http://localhost:5287/api/health/healthCheck --> Company

排查与修复方案 #

1. 先确认后端应用可用性 #

在Nginx服务器上执行以下命令，逐个验证ASP.Net应用是否能正常响应：

curl http://localhost:5160/api/health/healthCheck
curl http://localhost:5291/api/health/healthCheck
curl http://localhost:5176/api/health/healthCheck
curl http://localhost:5287/api/health/healthCheck

如果命令返回非200状态或无响应，先解决应用自身的启动、端口监听问题，再排查Nginx配置。

2. 修正Nginx代理配置中的核心问题 #

（1）调整HTTP协议版本

ASP.Net Core应用默认使用HTTP/1.1，当前配置中的proxy_http_version 1.0会导致兼容性问题，需改为：

proxy_http_version 1.1;

（2）修复路径转发错误

当前location /auth代理到http://0.0.0.0:5160时，Nginx会把请求路径/auth/api/health/healthCheck完整转发到后端，变成http://0.0.0.0:5160/auth/api/health/healthCheck，但后端应用的健康检查路径是/api/health/healthCheck，多了/auth前缀会导致404。

需给proxy_pass末尾添加斜杠，让Nginx去掉location前缀后再转发：

location /auth {
    proxy_pass http://0.0.0.0:5160/;
    # 其他配置保持调整后的内容
}

同理，/company、/equipment、/featureflags的proxy_pass都需要添加末尾的斜杠。

（3）优化Upgrade与Connection头配置

如果你的应用不需要WebSocket支持，可以直接删除proxy_set_header Upgrade $http_upgrade;和proxy_cache_bypass $http_upgrade;这两行；如果需要WebSocket，需调整Connection头并添加map规则：

在http块最上方添加：

map $http_upgrade $connection_upgrade {
    default upgrade;
    '' close;
}

然后将每个location中的proxy_set_header Connection keep-alive;改为：

proxy_set_header Connection $connection_upgrade;

3. 验证Nginx配置并重启 #

执行以下命令检查配置语法是否正确：

nginx -t

如果输出test is successful，执行重启命令让配置生效：

nginx -s reload

4. 查看错误日志定位细节 #

如果问题仍存在，查看Nginx错误日志获取具体报错信息：

cat /var/log/nginx/error.log

日志中会包含连接超时、权限不足、后端无响应等具体原因，针对性解决。

5. 检查防火墙与端口权限 #

• 确认服务器防火墙已开放80端口，允许外部访问；
• 确认后端应用的端口（5160、5287等）在服务器本地没有被防火墙拦截，Nginx可以正常连接这些端口。

内容的提问来源于stack exchange，提问作者JAKDev