Resolving Nginx 502 Bad Gateway Errors with SSL Handshake Issues and Buffer Configuration

The server returned a 502 Bad Gateway response when accessing http://192.168.20.69, with error logs showing SSL handshake failures and "peer closed connection" messages such as

2022/02/24 10:12:49 [error] 20021#0: *44 peer closed connection in SSL handshake (104: Connection reset by peer)

.

A quick curl test ( curl -I http://192.168.20.69) confirmed the problem, returning HTTP/1.1 502 Bad Gateway along with standard Nginx headers.

The original nginx.conf contains basic settings (user, worker_processes, events, etc.) and a server block listening on port 80 that proxies requests to https://nuget.cdn.azure.cn/v3/index.json. To address the errors, the configuration was updated with larger buffers and timeouts:

client_max_body_size 1024m;

client_body_buffer_size 10m;

client_header_buffer_size 10m;

proxy_buffers 4 128k;

proxy_busy_buffers_size 128k;

gzip on;

The server block now includes:

listen 80;

server_name 192.168.20.69;

location / {

root html;

index index.html index.htm;

proxy_pass https://nuget.cdn.azure.cn/v3/index.json;

}

Additional includes ( include sub/*.conf; and include to_internet/*.conf;) remain unchanged. After applying these settings, the SSL handshake succeeds and the 502 error is resolved.