I think I might have found where this Welcome to nginx. It seems to be triggered when an incomplete web address is entered(www. something TLD). I noticed using an addon with Firefox that it rolls back to the outside IP address. I did a Google search on nginx(pronounced engine-x) and there happens to be a definition on it at wikipedia. With that being said, it seems not to be malware since nginx is legitimate, but a problem with the software connection(if using Vista or above, do a diagnose and repair), or something that worse. Tech support at times needs as much help from your end to get this fixed. Also, www.nginx.org has a FAQ. An good answer to the problem(although it deal with a Facebook problem), does have the soultions to the problem. Go to www.nginx.org/en/docs/welcome_nginx_facebook.html . I hope this helps.