IP Proxy Forwarding Server (Linux/Ubuntu Server)

Setup server that can accept username and password: User connects to proxy via server IP with auth credentials. 1. Depending on auth credentials given, a proxy in another country is assigned to the request and everything is forwarded/returned to the requesting user credentials as if they were using the secondary proxy, but secondary proxy auth should never be shared with them. 2. Usage stats should be collected including, urls visited, bandwidth use, etc and stored in remote mysql db 3. Should be able to read from a list of blocked websites 4. Should have ability to modify strings if matches a certain text pattern 5. Blocking with certain error message based on credentials 6. Clear setup instructions should be given if proxy is needed in another location