Develop SMTP proxy server for e-mail archiving

The goal of this project is to develop SMTP proxy server that will archive all passed emails and attachments to a database. It's highly preferred to use existing open source software/modules/libraries whenever possible. In the best case scenario, the custom code should be used to integrate existing libraries and implement our custom business logic. Proxy code should rely on something field-proven Operation scenario: - SMTP proxy will be hosted on my Debian-based virtual servers - SMTP proxy will be put before user's own email server by changing DNS records (MX and [login to view URL] will point to proxy) - SMTP proxy will archive all sent emails to the database. This includes both messages sent from local users and messages received from other servers, with recipients in handled domains - SMTP proxy must provide local user authentication proxying (AUTH details will be forwarded to the original email server, the user will receive proxied response from that server) - No local authentication or domains configuration. Everything will be proxied - One instance of SMTP proxy will handle multiple destination servers - SMTP Proxy will bind to multiple IP addresses. Each address will be unique for the destination server. The proxy will distinct destination servers based on local IP where it received the connection. Ie we have 10 IP addresses on the server. If remote connection is made to local IP1 than we know to proxy all communications to the original mail server of user1 SMTP Proxy must support: - RFC-compliant SMTP services - On each provided local IP it should bind to all commonly used ports (25, 587, 465 for SSL/TLS) - For each unique local IP, it must be able to use proper SSL certificate provided by customer with no security warnings - Plain, STARTTLS, SSL/TLS communications on public interface (unique local IP) - Plain, STARTTLS, SSL/TLS communications with current users email server - Storing of email details to database (sender, recipients, cc/bcc's, subject, body, text version of body, attachments, headers) - Passing of original source IP address as a header in communications with destination email server SMTP Proxy configuration will consist of: - local IP mapped to a set of parameters: -- destination mail server and port. There can be multiple entries to implement simple failover (try next destination server if current one fails) -- list of ports to listen on public interface -- what authentication methods to support on public interface -- optional SSL key/certificates -- database server IP, user, password - for email contents storage No additional features required such as anti-spam, anti-virus and so on. Only proxy + store emails to database. Good starting points are: - nodejs smtp-server: [login to view URL] - nodejs haraka: [login to view URL] - [login to view URL] - Anti-Spam SMTP Proxy (ASSP) server written in perl - [login to view URL] - smtproxy - [login to view URL] - [login to view URL] In your bids please state wich of the existing libraries/projects are you planning to use and what's your experience with that project and in general SMTP/mail software development. Delivered project must include full, documented, unobfuscated, source code with no licensing and usage restrictions and written author's statement passing all rights to developed code