If the HOST header is OK when you do your test, then please try 0.7.51.
There is a bug of server_name issue fixed in 0.7.51

2009/4/13 alf

> Hello :)
>
> I have been trying to wrap my head around this, read a lot of docs, but I
> just cant seem to understand, so if anyone could enlighten me.
>
> My example:
>
> I want to set up a default virtual server (vhost) and a spesific vhost.
>
> 1. Does the sequence of these two server blocks in the nginx.conf matter?
>
> 2. I tried something like this:
>
> server {
> listen 80;
> server_name mydomain.com;
> index mydomain.html;
> }
>
> server {
> listen 80 default;
>

> server_name _;
> index default.html;
> }
>
> but now mydomain.com allways shows default.html. if i remove "default" and
> put that same (the second) server on the top it all works fine..
>
> I would really like to know what is really going on here behind the scenes,
> any info much apresiated.
>
> alf :)
>
> Posted at Nginx Forum:
> http://forum.nginx.org/read.php?2,1013,1013#msg-1013
>
>
>