Nixsys Public Access UNIX System

The Mail System at Nixsys PAUS:



One component setting Nixsys PAUS apart from other free and commercial service providers is the Mail System. Not only the local mail clients found on the server, but also the Secure IMAP, Secure POP3, and Secure WebMail servers use a unified mail storage system. Additionally, the GPG keyrings generated and used by the Secure WebMail server are also accessed (default behavior) by local mail clients on Nixsys PAUS. Our Mail System also supports DSN, which users may configure to enable notifications for their e-mail messages.

In the unlikely, but possible, event of the Mail System being unreachable for any reason, e-mail sent to will queue on our backup MX host to be delivered at a later time. Thus, no mail should ever be lost due to downtime. Our backup MX host runs a mail filter to identify UCE b.k.a. "spam". Unfortunately, this results in more of these messages being delivered to this system; however, they are marked as "SPAM" in the Subject header.

Local Mail Clients

These programs are available using a command line interface (CLI) through a SSH connection to Nixsys PAUS. Each link describes the functions of various mail clients accessible on the server. Other mail clients are available on the server, however these clients are incompatible with the Mail System. Users may continue to use these clients, but full integration with the Mail System is not possible and not supported by the administration.


Text-based MIME mail client with PGP support


BSD mail utility with MIME extensions


a Program for Internet News and Email (PINE)

Mailing Lists


Public Folders

Users have access to over 3.5 GB of space via two (2) Public Folders, Drop_Box and Drop_Box2. All users may move messages from any of their mail folders to subdirectories of the Public Folders. For example, User A moves or copies a message from his INBOX to the Files folder in Drop_Box2. Anyone can read this message, but only User A can delete it. Having this space available is useful when a user prefers to move / copy a message to a Public Folder rather than send it to everyone on the system.

The Local Mail Clients, Secure IMAP / Secure POP3 Clients, and the Secure WebMail interface all access Public Folders differently. Please read the section(s) relative to your choice(s) of Mail System access for an understanding of Public Folder utilization in relation to your client.

Secure IMAP / Secure POP3 Clients

Access to the Mail System is also available to Secure IMAP / Secure POP3 clients. Security mechanisms are in place for accessing mail using either one of these protocols. Below are platform specific sections with information regarding mail client configuration for different software packages.

MUAs can be configured as Secure IMAP and / or Secure POP3 clients, depending on the needs of the user. The main difference between the configurations exists in accessing Public Folders. With the former configuration, utilizing Public Folders is possible and in the latter it is not. The choice of configuration depends on whether or not a user wishes to transfer messages to those folders.

Secure IMAP / Secure POP3 Clients for Windows OSes

Outlook Express 6

Instructions for configuration. Currently tested on Windows XP.

IncrediMail / Mozilla Mail / Thunderbird

This detailed setup was written using Thunderbird. However, the configuration is almost identical when using IncrediMail and Mozilla Mail. Currently, only tested on Windows XP. Download these software packages free from the IncrediMail Site and the Mozilla Product Page.

Secure IMAP / Secure POP3 Clients for Macintosh OSes


Secure IMAP / Secure POP3 Clients for *nix and *nix-like OSes

Mozilla Mail / Thunderbird

Almost identical setup as Windows OSes. Currently, only tested on NetBSD. Download free from the Thunderbird Product Page.

Secure Mail Server

Nixsys PAUS has the capability to transmit e-mail over a secure channel. Normally, e-mail is sent in the clear. However, when the Mail Server connects to another system which offers the ability to negotiate transfers using TLS / SSL, the Mail Server switches to Secure mode, and thus an encrypted session is established.

Not only is the message encrypted, but also the FROM: and TO: headers as well. In theory, anyone monitoring the connection wouldn't be able comprise a list of affiliated parties, effectively destroying the ability to map a social network. Transmitting e-mail over a secured channel is only possible if the mail servers on both systems have a secure mode enabled.

Secure WebMail interface

This section describes the Secure WebMail interface in detail. Reading the TLS / SSL section is necessary to understand how to securely connect to the Secure WebMail interface. Failure to properly initate a secure connection to the Secure WebMail interface may jeopardize the security of user accounts. After configuring a web browser to initate secure connections to this site, continue to the Secure WebMail section to discover other features this interface provides.

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