SERVER_NAME and fastcgi

[KyleChristensen]

Forgive me if this has been covered before, but I didn't see anything
while searching.

I have a server setup similar to:

server {
	listen	80;
	server_name	domain.com someotherdomain.com somethirddomain.com;
	rewrite "^(.*)$"        http://www.domain.com$1       permanent;
}

server {
	listen	80;
	server_name	www.domain.com *.domain.com;
	server_name_in_redirect off;

	
}

I had some issues with nginx redirecting to *.domain.com when people
would omit a trailing / on physical directories in requests, the only
fix I was able to ascertain was setting it up as I have mentioned.

At any rate, if a client makes a request that bypasses our loadbalancer
directly via wwwX.domain.com, it gets caught by the second server block
as intended. The problem however is that $server_name gets set to the
first match in the server_name directive (as mentioned in the
documentation). My fastcgi_param for SERVER_NAME is set to $server_name
(the default).

The problem is that I need the ability to discern that someone is
hitting a server directly via $_SERVER['SERVER_NAME'], and under this
default configuration I am unable to do so since even direct requests to
webservers end up having $server_name set to www.domain.com, rather than
what the Host: was set to (wwwX.domain.com).

I understand that there is also the $host variable, but I was not sure
what the best practice is as far as reliably duplicating the SERVER_NAME
functionality of Apache.

Any help would be appreciated!

Thanks,
-Kyle

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,130806,130806#msg-130806