How to generate url with sub domain to new url with query string?

[leakhina]

Hi everyone,

I'm very new with Nginx, and now I want to use Nginx to generate new url from the url user passed.
Example:
User type to browser like http://us.domain.com, and I want Nginx generates to http://www.domain.com/?portal=us or http://domain.com/?portal=us.

How can I rewrite the nginx to do this?

Best regards,
Leakhina

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,3235,3235#msg-3235