HHVM + Apache + Varnish + Drupal 404 - apache

Question

This seems like quite an odd thing to be happening, but I'm getting 404 responses but the pages are still displaying as expected.
I do have a slightly odd setup on this server, as we're running HHVM for PHP pages and using Varnish as we need to direct some of the pages to our old server.
We're running Drupal on this server and it seems to work fine except the 404 response seems to be stopping the login form from working.
I was going to add some images to show what's going on, but unfortunately don't have enough reputation....
here's the what we get from a GET -Sed request
pete#pete-work ~ $ GET -Sed http://beta.newint.org/user
GET http://beta.newint.org/user
404 Not Found
Cache-Control: no-cache, must-revalidate, post-check=0, pre-check=0
Connection: close
Date: Wed, 27 May 2015 15:14:23 GMT
Via: 1.1 varnish
Age: 0
Server: Apache
Vary: Accept-Encoding
Content-Language: en
Content-Type: text/html; charset=utf-8
Expires: Sun, 19 Nov 1978 05:00:00 GMT
Client-Date: Wed, 27 May 2015 15:14:23 GMT
Client-Peer: 178.79.141.247:80
Client-Response-Num: 1
Client-Transfer-Encoding: chunked
ImageToolbar: false
Link: <http://beta.newint.org/user>; rel="canonical",<http://beta.newint.org/user>; rel="shortlink"
Title: User account | Site-Install
X-Generator: Drupal 7 (http://drupal.org)
X-Meta-Charset: utf-8
X-Meta-Generator: Drupal 7 (http://drupal.org)
X-Meta-Viewport: width=device-width, maximum-scale = 1.0
X-Powered-By: HHVM/3.7.0
X-Varnish: 1786764394
And then bypassing varnish and going straight to apache
pete#pete-work ~ $ GET -Sed http://beta.newint.org:8080/user
GET http://beta.newint.org:8080/user
404 Not Found
Cache-Control: no-cache, must-revalidate, post-check=0, pre-check=0
Connection: close
Date: Wed, 27 May 2015 15:14:31 GMT
Server: Apache
Vary: Accept-Encoding
Content-Language: en
Content-Type: text/html; charset=utf-8
Expires: Sun, 19 Nov 1978 05:00:00 GMT
Client-Date: Wed, 27 May 2015 15:14:32 GMT
Client-Peer: 178.79.141.247:8080
Client-Response-Num: 1
Client-Transfer-Encoding: chunked
ImageToolbar: false
Link: <http://beta.newint.org:8080/user>; rel="canonical",<http://beta.newint.org:8080/user>; rel="shortlink"
Title: User account | Site-Install
X-Generator: Drupal 7 (http://drupal.org)
X-Meta-Charset: utf-8
X-Meta-Generator: Drupal 7 (http://drupal.org)
X-Meta-Viewport: width=device-width, maximum-scale = 1.0
X-Powered-By: HHVM/3.7.0
Any ideas?

Answer 1

Turns out this was simply due to mod_rewrite not being enabled.