An email proxy server system gives the user access to all of their email accounts through a unified port. The proxy server maintains a mail registration database associating the user's ID with multiple email accounts, which may be hosted on different Internet providers and otherwise. The email messages stored on the email hosts may be in POP3 format, which configuration the proxy server imitates to give the user an impression of transparent access to all of their email accounts. Because the ability to access individual mail boxes is unbound from particular internet addresses, one user may maintain any number of email mail boxes at different hosting servers, and change those addresses, without having to reprogram client, server, and other software. Moreover, the presentation of the integrated interface of the invention permits system administrators to attach service modules, such as billing and other packages directly to the proxy server to serve each of the different email accounts, without having to tailor those individual services to individual hosts hardware.