Nginx到iis转发错误400

Question

Please help me. I have iis server and nginx proxy on it. When i connected to my nginx I get sometimes 400 Bad Request (Invalid hostname) error and when i press F5 and reload page my site loading correct (200 code) but without scripts\\css... and when I press F5 angain 400 error and so on.

iis on http://localhost:81

I tried with two nginx configs:

First

  location / {
            proxy_pass http://localhost:81;
            proxy_set_header    Host            $host;
            proxy_set_header    X-Real-IP       $remote_addr;
            proxy_set_header    X-Forwarded-for $remote_addr;
            port_in_redirect off;
            proxy_connect_timeout 300;
        }

Second

 location / {
            proxy_pass http://localhost:81;
            proxy_set_header Host $host;
            proxy_set_header X-Accel-Expires 0;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        }

Both first and second config have this error. Nginx of 1.6.2 version.

Nginx error.log is empty. Nginx access log like this

217.66.152.89 - - [16/Mar/2015:23:42:56 +0300] "GET / HTTP/1.1" 400 334 "-" "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.89 Safari/537.36"
217.66.152.89 - - [16/Mar/2015:23:42:58 +0300] "GET / HTTP/1.1" 200 689 "-" "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.89 Safari/537.36"
217.66.152.89 - - [16/Mar/2015:23:43:01 +0300] "GET / HTTP/1.1" 400 334 "-" "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.89 Safari/537.36"
217.66.152.89 - - [16/Mar/2015:23:43:03 +0300] "GET / HTTP/1.1" 200 689 "-" "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.89 Safari/537.36"

iis logs have only 200 and 304 codes

Request headers

Accept:text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Encoding:gzip, deflate, sdch
Accept-Language:ru-RU,ru;q=0.8,en-US;q=0.6,en;q=0.4
Cache-Control:max-age=0
Connection:keep-alive
Cookie:mode=undefined; view=undefined
Host:(this is my host)
If-Modified-Since:Mon, 16 Mar 2015 12:56:48 GMT
If-None-Match:"4e905caae85fd01:0"
User-Agent:Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.89 Safari/537.36

I hope for your help.

Answer 1

Had the same issue. It was caused by the fact that the server DNS name was resolving to an IPv4 address only, when "localhost" had both IPv4 and IPv6.

When NGINX tried to resolve an upstream " http://localhost " it was getting "::1" and switching to IPv6 - but HTTP.SYS (IIS network layer for the sake of discussion) later got an IPv4 address for the name specified in a "Host:" header.

This situation is not properly handled, despite the fact that the symbolic name, "localhost", IPv4 address and "::1" IPv6 one actually belong to the same machine.

Workaround - remove proxy_set_header Host $host; directive or use numeric upstream address in proxy_pass URI.