Nginx cross-city agent Internet access

Requirements:

A city---vpn---B city (server location), C city access to B city server needs to go public network, so B city needs Opened the public network, but B city has no public network ip assigned to the host, plans to use the proxy to access the Internet.
The plan is determined to be through nginx agent, C city----public network-------A city---vpn-----B city (server). 1. Map a public network address and port to the host. 2, DNS 3, nginx proxy configuration [root @ wall nginx] $ cat nginx.conf # basicuser nginx; worker_processes 1; pid /var/run/nginx.pid;worker_rlimit_nofile 202400; events {use epoll; worker_connections 202400;} http {fastcgi_connect_timeout 300s; fastcgi_send_timeout 300s; fastcgi_read_timeout 300s; include mime.types; default_type application /octet-stream; fastcgi_intercept_errors on; charset utf-8; server_names_hash_bucket_size 128; client_header_buffer_size 4k; large_client_header_buffers 4 32k; client_max_body_size 999m; sendfile on; tcp_nopush on; keepalive_timeout 60; tcp_nodelay on; client_body_buffer_size 512k; proxy_connect_timeout 5; proxy_read_timeout 28400; proxy_send_timeout 28400; proxy_buffer_size 16k; proxy_buffers 4 64k; proxy_busy_buffers_size 128k; proxy_temp_file_write_size 128k; gzip on; #gzip_disable " msie6 "; gzip_disable " MSIE [1-6] \\ . "; gzip_min_length 1k; gzip_buffers 4 16k; gzip_http_version 1.1; gzip_comp_level 2; gzip_types text /plain application /x-javascript text /css application /Xml; gzip_vary on; #server_tag off; #server_info off; #server_tokens off; ### 2012-12-19 change nginx logslog_format main '$ http_x_forwarded_for - $ remote_user [$ time_local] " $ http_host " " $ request " '' $ status $ body_bytes_sent " $ http_referer " '' " $ http_user_agent " $ request_time $ remote_addr '; ########################## ############################################################################ ####################################### load vhostinclude /etc/nginx/conf.d/* .conf;} [root @ wall nginx] $ cdconf.d /fastcgi_params.default mime.types.default scgi_params.defaultfastcgi.conf koi-utf nginx.conf uwsgi_paramsfastcgi.conf.default koi-win nginx.conf.default uwsgi_params. defaultfastcgi_params mime.types scgi_params win-utf [root @ wall nginx] $ cd conf.d /[root @ wall conf.d] $ lswall.conf [root @ wall conf.d] $ cat wall.confupstream wall {server 192.168. 1.2: 80; (B city server address) #check interval = 3000 rise = 2 fall = 5 timeout = 30000;} server {listen 83; server_name wall *; location /{proxy_next_u pstream http_502 http_504 error timeout invalid_header; proxy_set_header Host $ host; proxy_set_header X-Real-IP $ remote_addr; proxy_set_header X-Forwarded-For $ proxy_add_x_forwarded_for; #proxy_set_header X-Forwarded-Proto https; proxy_pass http: //wall; expires off;} }