Nginx Vhost configuration on Debian 7.0 32-bit

Hi,

I have installed Debian 7.0 32-bit on VPS. I have installed Nginx, php exactly as described in http://www.howtoforge.com/installing-nginx-with-php5-and-php-fpm-and-mysql-support-lemp-on-debian-wheezy
I can see Nginx welcome page when I open server IP address in the browser.
When I open any php page, it is getting downloaded, not opening in the browser.
I have 2 domains e.g.: domain1.com and domain2.com
I want server access to both IPv4 and IPv6
For domain1.com, I also want a subdomain e.g. blog.domain1.com hosted.
Only for domain1.com I want both http port 80 as well https port 443 access.
I have configured /etc/nginx/sites-available/default page as below.
Error 404 page is missing.php
Original configuration

# You may add here your
# server {
#	...
# }
# statements for each of your virtual hosts to this file

##
# You should look at the following URL's in order to grasp a solid understanding
# of Nginx configuration files in order to fully unleash the power of Nginx.
# http://wiki.nginx.org/Pitfalls
# http://wiki.nginx.org/QuickStart
# http://wiki.nginx.org/Configuration
#
# Generally, you will want to move this file somewhere, and start with a clean
# file but keep this around for reference. Or just disable in sites-enabled.
#
# Please see /usr/share/doc/nginx-doc/examples/ for more detailed examples.
##

server {
	#listen   80; ## listen for ipv4; this line is default and implied
	#listen   [::]:80 default_server ipv6only=on; ## listen for ipv6

	root /usr/share/nginx/www;
	index index.html index.htm;

	# Make site accessible from http://localhost/
	server_name localhost;

	location / {
		# First attempt to serve request as file, then
		# as directory, then fall back to displaying a 404.
		try_files $uri $uri/ /index.html;
		# Uncomment to enable naxsi on this location
		# include /etc/nginx/naxsi.rules
	}

	location /doc/ {
		alias /usr/share/doc/;
		autoindex on;
		allow 127.0.0.1;
		allow ::1;
		deny all;
	}

	# Only for nginx-naxsi used with nginx-naxsi-ui : process denied requests
	#location /RequestDenied {
	#	proxy_pass http://127.0.0.1:8080;    
	#}

	#error_page 404 /404.html;

	# redirect server error pages to the static page /50x.html
	#
	#error_page 500 502 503 504 /50x.html;
	#location = /50x.html {
	#	root /usr/share/nginx/www;
	#}

	# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
	#
	#location ~ \.php$ {
	#	fastcgi_split_path_info ^(.+\.php)(/.+)$;
	#	# NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini
	#
	#	# With php5-cgi alone:
	#	fastcgi_pass 127.0.0.1:9000;
	#	# With php5-fpm:
	#	fastcgi_pass unix:/var/run/php5-fpm.sock;
	#	fastcgi_index index.php;
	#	include fastcgi_params;
	#}

	# deny access to .htaccess files, if Apache's document root
	# concurs with nginx's one
	#
	#location ~ /\.ht {
	#	deny all;
	#}
}


# another virtual host using mix of IP-, name-, and port-based configuration
#
#server {
#	listen 8000;
#	listen somename:8080;
#	server_name somename alias another.alias;
#	root html;
#	index index.html index.htm;
#
#	location / {
#		try_files $uri $uri/ =404;
#	}
#}


# HTTPS server
#
#server {
#	listen 443;
#	server_name localhost;
#
#	root html;
#	index index.html index.htm;
#
#	ssl on;
#	ssl_certificate cert.pem;
#	ssl_certificate_key cert.key;
#
#	ssl_session_timeout 5m;
#
#	ssl_protocols SSLv3 TLSv1;
#	ssl_ciphers ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv3:+EXP;
#	ssl_prefer_server_ciphers on;
#
#	location / {
#		try_files $uri $uri/ =404;
#	}
#}

I have done below changes

# You may add here your
# server {
#	...
# }
# statements for each of your virtual hosts to this file

##
# You should look at the following URL's in order to grasp a solid understanding
# of Nginx configuration files in order to fully unleash the power of Nginx.
# http://wiki.nginx.org/Pitfalls
# http://wiki.nginx.org/QuickStart
# http://wiki.nginx.org/Configuration
#
# Generally, you will want to move this file somewhere, and start with a clean
# file but keep this around for reference. Or just disable in sites-enabled.
#
# Please see /usr/share/doc/nginx-doc/examples/ for more detailed examples.
##

server {
	listen   80; ## listen for ipv4; this line is default and implied
	listen   [::]:80 default_server ipv6only=on; ## listen for ipv6

	root /usr/share/nginx/www/domain1.com;
	index index.html index.php;

	# Make site accessible from http://localhost/
	server_name domain1.com;

		location /doc/ {
		alias /usr/share/doc/;
		autoindex on;
		allow 127.0.0.1;
		allow ::1;
		deny all;
	}

	# Only for nginx-naxsi used with nginx-naxsi-ui : process denied requests
	#location /RequestDenied {
	#	proxy_pass http://127.0.0.1:8080;    
	#}

	error_page 404 /missing.php;

	# redirect server error pages to the static page /50x.html
	#
	#error_page 500 502 503 504 /50x.html;
	#location = /50x.html {
	#	root /usr/share/nginx/www;
	#}

	# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
	#
	location ~ \.php$ {
		fastcgi_split_path_info ^(.+\.php)(/.+)$;
	#	# NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini
	#
	#	# With php5-cgi alone:
		fastcgi_pass 127.0.0.1:9000;
	#	# With php5-fpm:
		fastcgi_pass unix:/var/run/php5-fpm.sock;
		fastcgi_index index.php;
		include fastcgi_params;
	}

	# deny access to .htaccess files, if Apache's document root
	# concurs with nginx's one
	#
	location ~ /\.ht {
		deny all;
	}
}


# another virtual host using mix of IP-, name-, and port-based configuration
#
server {
	listen 80;
	listen   [::]:80;
	listen blog.domain1.com:80;
	server_name blog.domain1.com;
	root /usr/share/nginx/www/domain1.com/blog;
	index index.html index.php;

	location / {
		try_files $uri $uri/ =404;
	}
}

server {
	listen 80;
	listen   [::]:80;
	listen domain2.com:80;
	server_name domain2.com;
	root /usr/share/nginx/www/domain2.com;
	index index.html index.php;

	location / {
		try_files $uri $uri/ =404;
	}
}


# HTTPS server
#
server {
	listen 443;
	listen   [::]:443;
	server_name domain1.com;

	root /usr/share/nginx/www/domain1.com;
	index index.html index.php;

	ssl on;
	ssl_certificate /usr/share/nginx/domain1.crt;
	ssl_certificate_key /usr/share/nginx/domain1.key;

	ssl_session_timeout 5m;

	ssl_protocols SSLv3 TLSv1 TLSv1.1 TLSv1.2;
ssl_ciphers AES128-GCM-SHA256:ECDHE-RSA-AES128-HA256:RC4:HIGH:!MD5:!aNULL:!EDH;
	ssl_prefer_server_ciphers on;

	location / {
		try_files $uri $uri/ =404;
	}
}

I have removed apt-get --purge remove apache2.2-common
So .htaccess file is not necessary?
Please suggest what changes should I do.

Thanks.