When nginx is configured as reverse proxy, can it rewrite the host header to the downstream server like Apache's ProxyPreserveHost?

Question

I can't seem to find the equivalent of Apache's ProxyPreserveHost http://httpd.apache.org/docs/2.0/mod/mod_proxy.html#proxypreservehost option in nginx. This is required to reverse proxy to virtual hosts.

What it does is replace the host name the browser provides with the host name of the downstream server.

Does it exist?

score 12 · Answer 1 · edited Jul 31 '18 at 18:09

12

I think I found a solution to the problem. Sending the downstream server's host is the default behavior in nginx, and I had overridden it by using the directive:

proxy_set_header Host $host;

Which sends the host requested by the browser to the downstream server. Exactly the opposite of what I wanted.

So while nginx doesn't have an equivalent to Apache's ProxyPreserveHost, the same behavior can be achieved with the proxy_set_header directive, and nginx's solution is more general.

edited Jul 31 '18 at 18:09

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answered Nov 22 '09 at 06:53

1

Should be `proxy_set_header Host $http_host;`. – Rob Jan 02 '17 at 10:39
@Rob, `$http_host` doesn't exist according to Nginx docs: http://nginx.org/en/docs/varindex.html – Daniel Serodio Jul 31 '18 at 17:50
1

@DanielSerodio Actually, yes it does exist, at least for 99.99% of connections. See [the documentation](https://nginx.org/en/docs/http/ngx_http_core_module.html#var_http_). It also differs very subtly from `$host`. – Michael Hampton Jul 31 '18 at 18:35
@MichaelHampton I stand corrected, thanks for the link – Daniel Serodio Jul 31 '18 at 20:23

score 1 · Answer 2 · answered Aug 16 '13 at 03:58

A working example:

  set $s3_bucket 'SOMEBUCKET.s3.amazonaws.com';

  location / {
        send_timeout 5m;
        proxy_read_timeout 240;
        proxy_send_timeout 240;
        proxy_connect_timeout 240;
        proxy_http_version 1.1;
        proxy_set_header Host $s3_bucket;
        proxy_set_header Authorization '';
        proxy_hide_header x-amz-id-2;
        proxy_hide_header x-amz-request-id;
        proxy_ignore_headers "Set-Cookie";
        proxy_buffering off;
        proxy_intercept_errors on;
        proxy_redirect off;
        resolver 8.8.8.8;
        proxy_pass http://$s3_bucket;
        }

When nginx is configured as reverse proxy, can it rewrite the host header to the downstream server like Apache's ProxyPreserveHost?

2 Answers2