SunTM Internet Mail ServerTM is an extensible framework of cooperative modules that create an enterprise-wide and open standards-based messaging system. SIMS core components consists of the transfer agents, message store, and access units, and directory services.

Topics in this chapter include:

SIMS components overview

Message routing through SIMS

SIMS messaging data flow example

SIMS 4.0 system view

Supported standards

Supported clients

SIMS Components Overview

FIGURE 5-1 shows the components that comprise SIMS architecture. These components are:

Internet Message Transfer Agent

Message Store/Message Access

Directory Services

Sun Web Access Server

Delegated Management Console

Delegated Management Server

SIMS Administration Server

FIGURE  5-1 SIMS Components

See "Overview of SIMS 4.0 Components" on page 36 for overviews of each components of SIMS.

SIMS Optional Components

The following are SIMS 4.0 optional components that you may choose to add to your SIMS core server.

Additionally, you could install these options as stand-alone components on servers where SIMS is not installed.

Message Transfer Agent SDK

SIMS 4.0 Documentation Set

Remote Administration Console

SIMS Components Features

This section shows the features that the SIMS 4.0 product offers based on its individual components. Items that are identified as New are specific to the 4.0 release.

Internet Message Transfer Agent

Powerful anti-spam configuration with anti-relaying

SMTP authentication New

POP before SMTP authentication New

Scalable channel architecture

Domain hosting support New

DNS canonicalization to qualify non-FQDN names and normalize hostname aliases New

SDK for custom application development

Extensive address rewriting (including address reversal) and channel management facilities

Pipe channels supporting the IMTA through native Solaris programs

Message Store/Message Access

Domain hosting support New

Domain/subscriber authorized services through POP and IMAP New

APOP authentication for POP3 New

POP before SMTP connection New

Concurrent access to any message folder New

Secure Socket Layer (SSL) messages access

Message store utilities New

Integrated backup/restore utilities

Sun Web Access Server

Domain hosting support New

Domain and user provision New

HTML-based

Brandable

Single integrated UI to view email, directory, and calendar

Message attachment support

Sun Web server support New

High Availability support New

Delegated Management Console

Domain-level user creation and management New

Domain-level distribution list and management New

End-user personal preferences setup New

Customizable and brandable New

HTML-based application New

SIMS Administration Console

Netscape browser support New

Domain creation and deletion New

Domain service restrictions set up New

Domain-level user creation and management New

Distribution list setup and management New

Server statistics

Server components configuration

Server monitoring and queue status

Starting and stopping server

Purging deleted entries

Administration Utilities

Domain creation and management New

Domain and user authorized service restrictions New

Domain-level user creation and management New

Delegated administrator creation New

Bulk-loading new domain-level users New

Changing user authorized services New

Distribution list setup and management New

Service and performance monitoring New

Directory Services

Netscape Directory Services 4.1 support New

Sun Directory Services 3.1 support New

Multiprotocol, distributed, scalable, client/server-based global directory

LDAP v3 server New

Server failure rollover New

LDAP address referral in master/slave configuration New

Remote LDAP sever support New

Remote user authentication New

Domain Component (DC) tree structure support New

Other Optional Features

Message Transfer Agent SDK

SIMS 4.0 Documentation Set

Remote Administration Console

Overview of SIMS 4.0 Components

This section provides overviews of the SIMS components, as listed below:

Internet Message Transfer Agent

Message Store/Message Access

POP3/IMAP4 protocol

Directory Services

Sun Web Access Server

Delegated Management Console

Delegated Management Server

SIMS Administration Console

SIMS Administration Utilities

SIMS Server Man Pages

SIMS High Availability systems

Remote Administration Console

Message Transfer Agent SDK

Internet Message Transfer Agent

The Internet Message Transfer Agent (IMTA) routes, transports, and delivers Internet Mail (RFC 822) messages within the email system.

The IMTA performs all of its operations on a set of channels. The two types of channels are internal and external. An internal channel is an interface between the internal modules of the IMTA. Internal channels include the reprocessing, conversion, and defragmentation channels. These channels are not configurable from the SIMS Administration Console.

An external channel is an interface between the IMTA and another SIMS component, such as the Sun Message Store, or another component outside of SIMS (for example, the Internet or a local mail client). The external channels are configurable.

See Chapter 7, "Internet Message Transfer Agent," for detailed information on the IMTA component.

Message Store/Message Access

Sun Message Store is a dedicated data store for the delivery, retrieval, and manipulation of Internet email messages. This message store works with the IMAP4 and POP3 servers that are integrated with SIMS. It saves any message that conforms to RFC 822 specifications, and recognizes the Multipurpose Internet Mail Extensions (MIME) content format.

The advantage of the Sun Message Store is the ability to save only a single copy of any incoming message that is sent to a distribution list or multiple recipients, provided all recipients are on the same mail server. For example, if a message is sent to 20,000 users on the same server, only one master copy of the source message is saved in the store.

POP3/IMAP4 Protocol

Post Office Protocol Version 3 (POP3) is an implementation of the server side of the POP3 (RFC 1939) access protocol standard. Many popular mail clients currently use POP3.

Internet Mail Access Protocol Version 4 is an implementation of the server side of the standard IMAP4 protocol (RFC 2060). IMAP4 is used by client mail applications to access Internet email messages in distributed, enterprise/Internet-wide message stores. Messages are parsed on delivery to ensure the highest IMAP performance.

See Chapter 9, "Sun Message Store," for detailed information on the message store component.

Directory Services

SIMS 4.0 supports both the Netscape Directory Services as well as the Sun Directory Services. Integrated with SIMS is Sun Directory Services 3.1 that provides a multiprotocol, distributed, scalable, client/server-based global directory. It allows storing information such as user definitions, user profiles, network resource definitions and configuration parameters. It supports a range of naming, directory, and authentication protocols on the top of a shared and distributed repository.

Sun Directory Services 3.1 is ready for use with leading Web browsers, PC address book tools, and client software. It is fully compatible with other mail and directory applications.

See Chapter 8, "Directory Services," for information on the available directory services and components, and directory replication.

Sun Web Access Server

Sun Web Access is a client application that gives end-users browser-based access to the SIMS 4.0 email and Name Directory services and to the Solaris Calendar server. Sun Web Access is integrated with the SIMS 4.0 server system and centrally administered. See the Sun Internet Mail Server 4.0 Web Access Administrator's Guide for information on configuring and administering this server.

Delegated Management Console

Delegated Management Console is an enhancement to SIMS. It enables a service provider, a reseller of Internet services who provides email services for their customers (subscribers), to delegate the administration of that customer's mail domain to the customer. This delegated management can perform on a prescribed set of users and groups within a prescribed set of operations of the customer's mail domain.

While SIMS provides all the email facilities for a hosted domain, the Delegated Management Console enables the SP's subscribers to create and manage domain-level users and distribution lists as well as setting up end-user personal preferences within the user's hosted domain.

See Chapter 6, "Domain Hosting with SIMS," for domain hosting feature components and specifications.

See Chapter 11, "Delegated Management Administration," for summaries of tools that different types of administrators could use to perform domain hosting administrative tasks.

See the Sun Internet Mail Server 4.0 Delegated Management Guide for descriptions of the Delegated Management Console and the tasks associated with the console.

Delegated Management Server

The Delegated Management server provides directory services to the Delegated Management Console. Once it has interpreted a request from the Delegated Management Console, the server performs the necessary access controls checks. If the access controls are positive, it then applies the changes to the Directory Services and relays the directory's response back to the Delegated Management Console. If the access controls are negative, the server denies the access to the Delegated Management Console.

SIMS Administration Console

The SIMS Administration Console is a GUI-based administration tool that the SIMS administrator can use to setup, maintain, configure, and monitor the SIMS system, including the domain hosting capabilities.

The console allows configuring SIMS components such as Message Transfer Agent (IMTA), Sun Messages Store (MS), Message Access (MA), Directory Services, and monitoring and queue status.

The SIMS administrator at the SP site can use the console to create hosted domains as sub-domains within its own domain as well as peer domains. The SIMS administrator is enabled to delegate these tasks to the delegated administrator without compromising the integrity or security of the server.

Alternatively, the SIMS administrator could perform user and distribution list administrative tasks for hosted domains by using the SIMS Administration Console at the SP site.

See Chapter 10, "SIMS Adminstration Console," to learn about the SIMS Administration Console services and components.

See Chapter 11, "Delegated Management Administration," for summaries of the tasks and tools that are available to the delegated administrators.

See Chapter 11, "Configuration Files" in the The Sun Internet Mail Server 4.0 Installation Guide for lists of files that are associated with each SIMS component.

See the Sun Internet Mail Server 4.0 Administration Guide for instructions on how to configure, maintain, monitor, and troubleshoot your mail server using the SIMS Administration Console.

SIMS 4.0 Administration Utilities

The SIMS 4.0 Administration Command Line Interface (CLIs) provides administrators with a set of command line utilities to manage a SIMS system. The current methods of managing a SIMS system include manually editing configuration files, running various component specific scripts or executable, and running the SIMS Administration Console.

These methods require intimate knowledge of the underlying components as well as their interdependencies and is prone to error. However, managing a large number of users or automating repetitive tasks is not feasible through the SIMS Administration Console. The CLIs will provide another method of managing a SIMS system which will alleviate these problems.

Like the SIMS Administration Console, the SIMS administrator at the SP site can use the CLIs to create and manage hosted domains, as well as to delegate an administrator to administer users and distribution lists within that hosted domain.

Both the SIMS administrator and the delegated administrator could use the CLIs to create users and distribution lists within a hosted domain, provided that they both have UNIX accounts.

See the Administration CLI man pages for descriptions of command-line utilities and detailed information about the arguments and attributes relevant to each command.

SIMS Server man pages

UNIX manual reference pages for the SIMS server command-line utilities and configuration files. The man pages provide detailed information about the arguments and attributes relevant to each utility. The configuration file man pages provide detail about the file's structure and parameters.

SIMS High Availability System

SIMS 4.0 is a high-performance, highly scalable mail delivery and access system. Since mail is critical to enterprises and SP customers, many SIMS customers wish to run SIMS on a cluster to get higher availability of their mail system through fail-over to a surviving member of the cluster.

For this reason, SIMS 4.0 provides Asymmetric High Availability (HA) configurations. In this configuration, all the SIMS binaries, configuration files, message queues, and message stores reside on a shared disk. When a switch-over occurs, the disk is unmounted from the failing system and mounted on the surviving system.

See the Sun Internet Mail Server 4.0 Installation Guide for instructions to install and configure SIMS/HA, and for descriptions of the architecture of this system.

Remote SIMS Administration Console

The Remote SIMS Administration Console allows you to remotely access and use the SIMS Administration Console on any other Solaris, Windows 95, and NT systems that is not running SIMS. It allows you to administer the SIMS server from a remote server.

Message Transfer Agent SDK

The Message Transfer Agent SDK is a set of C APIs for the Internet Message Transfer Agent (IMTA). It allows you to develop custom SMTP channels, such as a custom channel to send mail to a user's pager or to a fax machine.

Message Routing Through SIMS

Submitted messages from the Internet or local clients go to the IMTA via SMTP (Simple Mail Transport Protocol). If the message address is within the SIMS domain, the IMTA delivers the message to the message store. If the message is addressed to another domain, the IMTA relays the message to another transport agent on the Internet or Intranet.

Messages to the local domain are stored in the message store or the traditional UNIX /var/mail file system depending on how the system is configured. Once messages are delivered to the appropriate mailbox, they can be retrieved, searched for, and manipulated by IMAP4 or POP3-based mail clients.

The IMTA uses the LDAP directory to retrieve local user and group address information. When the IMTA receives a message, it uses the directory information to determine where the message should be delivered. The message store uses the Directory services to authenticate users logging into their mailboxes. The message store also obtains information about user message quota limits and Message store type (IMAP or POP). Outgoing client messages go to the SMTP channel in the IMTA. The IMTA sends the message to an Internet IMTA or, if the address is local, to the message store.

SIMS Messaging Data Flow Example

FIGURE 5-2 shows the routing of messages through the SIMS system.

FIGURE  5-2 SIMS Message Routing

The message data flow is as follows:

SIMS System View

FIGURE 5-3 shows a SIMS system that contains all SIMS components and the relationship between these components. It also shows the connection between this SIMS server and the clients that SIMS supports.

See "Supported Clients" on page 44 for a list of clients that SIMS supports.

FIGURE  5-3 SIMS System View

Supported Standards

TABLE 5-1 shows the standards that the SIMS IMTA and message store and Access components use. The table also identifies the types of message store that SIMS supports.

TABLE  5-1   Supported Standards

Component	Protocol
Internet Message Transfer Agent	Transport protocols: ESMPT, MIME, UUCP
(IMTA)	Value added channels: FAX, Pager, Printer (future)
Message Store and Access	Message Access Protocols: IMAP, POP3
(MS/MA)	Message Stores: Sun Message Store, /var/mail

Supported Clients

Sun Internet Mail Server supports a wide range of clients. It features a single message store for POP3, IMAP4, and OpenWindows Mailtool environments, which enables you to have a single mail server for PC, UNIX, and Macintosh environments.

Sun Internet Mail Server is tested with some of the most popular Internet mail clients such as Netscape Messenger, Microsoft Outlook Express, Qualcomm's Eudora Pro, CommTouch Software's Pronto E-Mail, and NetManage's Z-Mail.

If you have existing investment in non-Internet standards-based clients such as Microsoft Windows Messaging Inbox or Microsoft Outlook, Sun Internet Mail Server software delivers tools to protect your investment. SIMS 4.0 contains MAPI service providers for IMAP and LDAP that give these clients access to SIMS.

Sun Internet Mail Server 4.0 software also features Sun Web Access, which enables accessing server-based email, calendar, and directory information by any standard Web browser. It enables users to stay in touch anytime, anywhere.