nginx: Use of proxy_set_header results in failed upstream connections

HamishC

10/13/22, 3:02 AM

I have a very basic nginx reverse proxy setup for openstreetmaps:

worker_processes  1;

error_log  logs/error.log  notice;
pid        logs/nginx.pid;

events {
    worker_connections  1024;
}

http {

  postpone_output 0;
  
  log_format logresponsetime '$remote_addr - $remote_user [$time_local] "$request" $status $bytes_sent "$http_referer" "$http_user_agent" $request_time $upstream_response_time';
  
  access_log logs/access.log logresponsetime;
  resolver 192.168.0.1 ipv6=off;

  #default proxy settings:
  proxy_http_version 1.1;
  proxy_set_header Connection "";
  proxy_read_timeout 600;
  proxy_ssl_server_name on;

  upstream tile.openstreetmap.org {
    server tile.openstreetmap.org:443;
    keepalive 10;
    keepalive_time 5m;
  }
   
  server {
    listen 480;
    access_log logs/osm.http.access.log logresponsetime;
    server_name $hostname;

    location / {
      resolver 192.168.0.1 ipv6=off;
      
      proxy_set_header User-Agent "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.77 Safari/537.36";

      proxy_pass https://tile.openstreetmap.org;
    }
  }
}

There is a line to set User-Agent header because OSM requires it and I need compatibility with a client that doesn't send a user agent string. However, when nginx sets this header, approximately 10% of requests fail (nginx returns 502 to client), and my nginx error log fills up with this:

2021/06/13 14:37:49 [error] 67240#87020: *71 connect() failed (10060: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond) while connecting to upstream, client: 127.0.0.1, server: server, request: "GET /16/64153/41313.png HTTP/1.1", upstream: "https://151.101.166.217:443/16/64153/41313.png", host: "localhost:480"

Without the proxy_set_header, everything is fine. The requests in this case are all being made from chrome, so the User-Agent as seen by the OSM servers should be the same in both cases. nginx version is 1.19.10 (windows). What am I doing wrong?

196

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nginx

reverse-proxy

Richard Smith

10/13/22, 6:47 AM

You need to place all of your `proxy_set_header` statements in the same block, if you want them all to apply. There are two `proxy_set_header` statements in your configuration and they are in different blocks.

HamishC

10/13/22, 7:07 AM

thanks @RichardSmith, problem solved! much appreciated

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: nginx: Use of proxy_set_header results in failed upstream connections

TH: nginx: การใช้ proxy_set_header ส่งผลให้การเชื่อมต่ออัปสตรีมล้มเหลว

RO: nginx: Utilizarea proxy_set_header are ca rezultat conexiuni eșuate în amonte

RU: nginx: использование proxy_set_header приводит к сбою восходящих подключений

VI: nginx: Việc sử dụng proxy_set_header dẫn đến kết nối ngược dòng không thành công

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