router - Is it possible to run Virtual Hosts (or equivalent) across several servers, but one public IP, using Tomato?

Here's my home setup. I have a single IP address provided by my ISP. I have one top-level-domain (TLD) and several sub-domains that point at that IP. Internet comes in through my cable modem and plugs into my AdvancedTomato router. I want to install several web servers on separate machines and have the router forward the traffic based upon the domain name. Here's a basic picture

    Internet
    |
    |
    └── example.com-x.x.x.x(router)
        ├── machine1-192.168.1.101
        │   ├── project11.example.com
        │   └── project12.example.com
        ├── machine2-192.168.1.102
        │   ├── project21.example.com
        │   └── project22.example.com
        └── machine3-192.168.1.103
            ├── project31.example.com
            └── project32.example.com

I have been able to do this already on a single machine using basic port forwarding on the router (everything on port 80 goes to machine1), then using Apache's VirtualHost's on that machine to open different websites.

    Internet
    |
    |
    └── example.com-x.x.x.x(router)
        ├── machine1-192.168.1.101
            ├── project11.example.com
            └── project12.example.com

My question: is it even possible to do this at the router level? If not, how do large websites set this up.I know HTTP is at the application level, and that's where the domain request is, so can the router even look at that information? Would I need a proxy server?

Also, should this be on server fault instead?

Answer

What you are describing is Reverse Proxy how do large websites set this up ? -- They have Proxy Servers behind routers

Yes it's possible at the router level but don't think just any router can do it

AdvancedTomato can do this directly from the UI. Enter the following into Web Services->Web Server->HTTP Section. Then Save and press the play button. Tomato adds some extra bits, so to verify it's the config you want, you can see it in /etc/nginx.conf (or look at /var/log/nginx/error.og if it failed)

    # Because end of http://nginx.org/en/docs/http/server_names.html
    server_names_hash_bucket_size  64; 


    # Adapted from NixCraft
    # http://www.cyberciti.biz/tips/using-nginx-as-reverse-proxy.html

    # Host required
    server {
        listen      80 default_server;
        server_name "";
        return      444;
    }        

    ## Start primary proxy ##
    server {
        listen       80;
        server_name  jira.example.com
                     confluence.example.com
                     stash.example.com
                     cacti.example.com;
        access_log  /var/log/nginx/log/lamp.example.access.log  main;
        error_log  /var/log/nginx/log/lamp.example.error.log;

        ## send request back to apache1 ##
        location / {
             proxy_pass  http://192.168.1.99/;
             proxy_redirect default;
             proxy_buffering off;
             proxy_set_header        Host            $host;
             proxy_set_header        X-Real-IP       $remote_addr;
             proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
        }
    }
    ## End ##



    map $http_upgrade $connection_upgrade {
        default upgrade;
        '' close;
    }

    # Websockets
    server {
        listen 8686;
        server_name other.example.com;
        location / {
            proxy_pass http://192.168.1.99:8686;
            proxy_redirect default;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection $connection_upgrade;
        }
    } 

Alternatively you can place a reverse proxy behind the router to redirect the traffic

I personally use DD-WRT -- i have read about it but haven't personally implemented Reverse Proxy at the router level DD-WRT Reverse Proxy