Nginx – Allow requests without a Host header

httphttp-headersnginx

When Nginx receives a request that's missing the Host header, it rejects it with a 400 response. As it should.

Is there any way around this?

There is a piece of hardware that needs to be able to make REST calls to my Nginx web server, but this device is not sending a Host header. There is nothing I can do about this, I have no control over the inner workings of this device.

This will be the only device communicating with my web server that lacks a Host header, and it will always be connected to the same location. The server is using name-based virtual hosts.

I've tried rebuilding my server using the headers-more-nginx module since I believe it can add headers to requests before they are processed. I added the following line to the server{} block for this virtual host:

more_set_input_headers  "Host: device.myserver.com";

But requests are still being rejected with a 400.

Edit:

I forgot to mention that these devices are currently able to make requests to a lighttpd 1.4.28 web server. I'm trying to get them working on Nginx. I can't find anything special in the lighttpd config files that should be allowing this to work, it seems like lighttpd just doesn't require this header.

Edit 2:

Results from tcpdump (I X'd out the stuff that I shouldn't put online):

POST http://XXX.XXX.XXX.com/index/get-next-command HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Connection: keep-alive
Content-Length: 62

user=XXX&pass=XXX&v=0103HTTP/1.1 200 OK
X-Powered-By: PHP/5.3.10-1ubuntu3.21
Set-Cookie: PHPSESSID=XXX; path=/
Set-Cookie: username=XXX; path=/
Set-Cookie: password=XXX; path=/
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache
Content-type: text/html
Transfer-Encoding: chunked
Date: Thu, 03 Dec 2015 19:37:56 GMT
Server: lighttpd/1.4.28

46

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{"XXX":"XXX","XXX":"XXX","parameters":[]}
0

Best Answer

From here: http://nginx.org/en/docs/http/server_names.html

Miscellaneous names

There are some server names that are treated specially.

If it is required to process requests without the “Host” header field in a server block which is not the default, an empty name should be specified:

server {
    listen       80;
    server_name  example.org  www.example.org  "";
    ...
}

If no server_name is defined in a server block then nginx uses the empty name as the server name.

So adding "" to your server_name seems to do what you want.

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