• United States



by Kimberly K. Miller

Wireless E-Mail: An Overview

Jan 05, 200511 mins
CSO and CISOData and Information Security

Wireless e-mail solutions need to be device-, network- and server-independent to grow with an enterprise’s mobile plans. A clear understanding of the features is critical in selecting a solution.

Wireless e-mail solutions act as a proxy on behalf of mobile users, ready to push or pull data. This server-based software interfaces directly with enterprise data sources, extracts the data and delivers it securely to the mobile device tailored to the device type, regardless of the location of the user.

Solutions deployed behind the firewall are the most secure approach to mobile e-mail delivery. Multiple servers may be necessary, depending on network configuration, usage, number of mobile clients, resiliency and load-balancing requirements. Wireless e-mail solutions provide end-to-end security, offer management, increase speed and add reliability to corporate local-area networks (LANs) that support mobile clients.

Client/server-based messaging platforms provide a single data store for e-mail, calendar, contacts and tasks, collectively known as e-mail/personal information manager (PIM), and support offline access and synchronization. Messages and changes on the device are the same as on the server and can be stored for offline use if the device can handle it. Gartner prefers client/server solutions that utilize the native e-mail client on the mobile device. This approach provides greater integration with other pre-loaded software applications.

A wireless e-mail solution should meet a minimum set of requirements for enterprise deployment:

  • Single data store for e-mail. All e-mail actions must immediately be processed in a central data store; there may be temporary copies on the device. Immediate action on PIM data is preferred but not required. A forwarding mechanism or redirector is not compliant. A browser-based-only model is not appropriate for business users because of the unpredictability of wireless coverage.
  • Demonstrated support of Microsoft Exchange. Solutions that additionally support Lotus Domino, Novell GroupWise, Internet Message Access Protocol (IMAP), Post Office Protocol 3 (POP3) or a combination are considered better solutions.
  • Solution sits behind the corporate firewall. This is the optimal and most secure approach to wireless e-mail delivery. Other approaches, such as desktop redirectors, represent security risks.
  • Offline support on a minimum of one of the following device types: Palm, Pocket PC, Research In Motion (RIM) or Symbian. Vendors who demonstrate support for more then one device are more versatile.
  • Support for the native e-mail client or an alternative e-mail client that offers enhanced functionality over the native application. Production shipment of wireless e-mail solution to enterprise customers.

The following advanced feature set is considered advantageous:

  • Support for two or more wireless networks and operators
  • Support for reading, forwarding or both of attachments.
  • Push-based e-mail support (as opposed to server-timed or device-timed, user-initiated or message-based synchronization through a mechanism like Short Message Service [SMS]).
  • Support for Lightweight Directory Access Protocol (LDAP) or Global Address List (GAL) (for example, for the ability to access the Directory for applications beyond e-mail).
  • Support for filtering, and a two-step retrieval process for selective download of e-mails, or setting up a retrieval process to read only the headers first.
  • Triple Data Encryption Standard (DES) encryption or equivalent end-to-end security.
  • Single or simplified process for procuring services (the vendor provides a distribution channel with a single source for support and services). Agreements with network vendors that ease the transfer of devices to different network providers are considered advantageous.
  • International support that includes not only support from local operators, but also the ability to connect the e-mail device reliably back to the home server located in a different country. SMS-initiated push methods are considered unreliable and are not considered viable in international scenarios.

Business Use

Enterprises get hooked on wireless e-mail, then look beyond the in-box for what other applications need to be made mobile. It is for this reason that enterprises should ask potential vendors, “What else can you do for me other then make my e-mail mobile?” Enterprises should not be so shortsighted and stop with wireless e-mail. Once users get the taste of wireless freedom and convenience – putting connection frustration aside – they will want more – as will the corporation when productivity gain and customer satisfaction/retention are realized.

Enterprises also desire the solution to support multiple device types, regardless of whether the enterprise supports those device types today. They want the option to do so in the future without having to worry about yet another wireless e-mail solution to support different device types.

Selection Guidelines

Selection guidelines expand the criteria used in the Mobile E-Mail/PIM Magic Quadrant to include additional features of the wireless e-mail solutions. These guidelines are the basis for the Wireless and Mobile E-Mail: Comparison Columns report that provides a side-by-side comparison of wireless e-mail solutions of the vendors on the Magic Quadrant for Wireless E-Mail/PIM, 2H03. It is important to note that not all features are available on all device types; this is a limitation in hardware and not necessarily a shortcoming of the software. For example, users cannot answer an e-mail with a voice call if the user is using a handheld that does not support voice.

Baseline Requirements

Messaging Server(s)

The three most common messaging servers on the market are Lotus Domino, Microsoft Exchange and Novell GroupWise. Messaging protocols include POP3 and IMAP4. POP3 is a store-and-forward e-mail protocol typically used to retrieve mail messages from a server. IMAP4 is for user access over the wide-area network (WAN) to Internet mail servers for managing mail folders, scanning message headers and downloading messages only; IMAP does not support other PIM features. Solutions that support Exchange plus Domino, GroupWise, IMAP, POP3 or a combination of these are considered better solutions.

Sits Behind Firewall

Wireless e-mail is installed on a dedicated server(s) behind the corporate firewall or inside the demilitarized zone (DMZ). This is the optimal and most secure approach to mobile e-mail delivery. Other approaches, such as desktop redirectors, which push e-mail from client desktops to outside services or forward e-mail from servers to outside services, represent security threats.

Single E-Mail/PIM Data Store

When a change is made on the handheld device (for example, deleting a message), it should be reflected on the server. How this is done is determined by the synchronization method that is used (see Synchronization Methods below). A forwarding mechanism (that is, forwarding and storing e-mails outside the firewall on an independent server) or redirector is not sufficient.

Device Types Supported

Vendors that support more than one device are considered a better choice. It is critical that the vendor supports current devices as well as has an eye on future mobile devices. Look carefully at the specific models and types of devices supported by these vendors. Don’t be lulled into a sense of security when vendors state that their products support any device over any network. That may be their ultimate goal in the future, but look at the reality of today.

The device type(s) will dictate the e-mail solution selected. Wireless e-mail vendors need to demonstrate to their customers that their products run on all device types that they state they support.

E-Mail Client

Solutions should support the device’s native e-mail client or an alternative e-mail client that offers enhanced functionality over the native system.

Offline Capabilities

All wireless e-mail solutions operate in real time; however, the ability to work offline is a more desirable option. The solution should support local e-mail/calendar at a minimum for offline operation on at least one device platform. Better solutions will support full e-mail/PIM functions when the device is offline. Not all device types can support offline capabilities; this is a hardware limitation and not one of software. Likewise, not all options are supported over the air.

Core and Advanced Features

Mobile Networks Supported

In order for a wireless application to be deployed and utilized, it must be available on a variety of mobile networks today as well as forthcoming services of tomorrow – namely third generation (3G). The solutions should be able to detect the type of wireless network they are in.

Other Connectivity Methods

Other connectivity methods include dial-up, 802.11a,b,g, Bluetooth and LAN for cradle use.

Synchronization Methods

It is critical to understand how the mobile mail synchronizes with the server in the enterprise network. Gartner has identified six types of synchronization methods for mobile mail. Server-timed is better if looking to control costs. Push-based is good for timeliness.

  • Push-based: In true push-based synchronization, the server tracks the device through IP addressing. Users can roam in and out of coverage, and the server strives to deliver messages when an opportunistic connection is located. There are other push-based synchronization methods that use an SMS ping to locate the user.
  • Server-timed: The server synchronizes with device at intervals determined by the IT department.
  • Device-timed: The device synchronizes with server at intervals determined by user.
  • User-initiated: Synchronization is left in the control of the user. The user pushes a button to synchronize with server (for example, Handspring).
  • Device-message-initiated: When message is sent, synchronization occurs (for example, Global System for Mobile Communication/general packet radio service [GSM/GPRS] systems or SMS).
  • Cradle synchronization: The device is set in a cradle for synchronization to occur; desktop software is required. Some solutions offer the cradle synchronization and wireless synchronization methods listed above.
  • Ask the vendor if all these methods are used across all e-mail/PIM functions on all devices. Some solutions only synchronize e-mail and calendar information.

Session Management

Types of session management include inactivity timeout, auto connect on send, manual reconnect or auto reconnect. Some solutions set up profiles for the device that tell the server if the device is communicating over a mobile network or in the cradle. Some application gateways hold a dropped wireless session open for a specified period of time; when the user returns to the covered area, the lost session is picked up right where it left off.

Management Capabilities

Most vendors offer some type of remote management capabilities to control software distribution, backups or user accounts.

Additional Applications Supported

It is important to know if the wireless vendor is capable of supporting additional back-end applications beyond e-mail/PIM. If the solution does not support other applications and the enterprise needs to take a sales force automation application mobile in the future, a separate application will have to be purchased and deployed. Some wireless e-mail vendors offer a developer’s kit or an open set of application programming interfaces to make legacy, proprietary or new client/server applications accessible wirelessly.

Desktop Client Required

Some solutions require a piece of software to be loaded onto the user’s desktop/laptop. Typically, software needs to be placed on the desktop/laptop for cradle synchronization, but no additional software is needed for wireless.

Technology Alternatives

Browser-Based Enterprise Solutions

Wireless e-mail is either browser-based or client/server-based, depending on the types of mobile devices supported. Browser-based platforms are for devices only capable of supporting Web browsers, also known as microbrowsers, such as WAP phones. With a browser-based platform, users are capable of sending and receiving data when the device is in the wireless network only. Messages and changes cannot be stored for offline use.

Hosted/Carrier-Based Solutions

Enterprises considering a hosted e-mail service from a mobile service provider or carrier should know which gateway platform the mobile operator is using and investigate the vendor’s viability as well as the capability and features of that platform. Choosing to go with a hosted service does not alter the selection guidelines. Enterprises should still hold the service provider offering up to the same measuring stick. The main difference between a carrier’s solution and one that the enterprise maintains is that the carrier’s solution does not sit behind the enterprise firewall. The mobile e-mail/PIM platform resides in the operator network and provides real-time access to corporate e-mail, PIM or documents. The caveat to this approach is that corporate data sits on a server outside the enterprise firewall. Carriers do employ security measures, but this is not the recommended approach to enterprise-class wireless e-mail.

Personal Services

Personal business users (a class of users defined as “prosumers”) pay a monthly fee to a service provider to gain access to corporate or personal e-mail boxes. Typically, all a user needs to do is download the software to his or her desktop and client device and contract for airtime with a qualified service provider. Enterprises need to be aware that their employees can be gaining access to corporate e-mail from an outside source.