Client-server email

What is client-server email?

With client-server email, you use an email client that provides a speedy user interface that continues to be available even when the device is offline. During such times, email messages that have been previously retrieved from the email server are stored in memory and may be read at the user’s convenience. Email messages that are sent whilst the device is offline are queued in memory until Internet connectivity is reestablished.

At the moment, client-server email systems that automatically retrieve email messages when they are received are often proprietary and may require the installation of special software at both the email client and server.

Other client-server email systems allow the user to specify when email is fetched, how frequently, and whether with or without user intervention. These email systems tend to use standard Internet email protocols that may also be used on your desktop PC, such as POP, IMAP and SMTP.

What are POP, IMAP, and SMTP?

There are two common protocols for fetching email and one common protocol for sending email:

• IMAP/POP (Internet Mail Access Protocol/Post Office Protocol) - common protocols for accessing a server-based email mailbox through your mobile device's email client - these protocols allow you to view message headers first to avoid downloading all emails in their entirety, thus saving cost, time and device memory.
• SMTP (Simple Mail Transport Protocol) - a common protocol used for sending email messages.

Whichever protocol is used, your email application connects to your email server through any of the network access methods supported by your mobile device - for example, WLAN, GPRS data or GSM data dial-up. Email access over public networks may be made more secure with SSL or TLS technology if they are supported by both your email server and the email application on your mobile device.

All Nokia business devices with a native email application support standard Internet email protocols.

Tell me more about email clients

Many mobile phones today come with a native email application. When this email application connects to an email server it is functioning as an email client.

These native email applications facilitate access to both private or business hosted email services. For private email accounts, the native application may connect to Internet email services like those provided by Yahoo and AOL. For business email, the application may connect to corporate email services on the corporate network, or to Internet Service Provider (ISP) mail servers if, for example, the corporate email service is hosted by an ISP.

In the case of business email, since corporate email servers are typically not reachable from the Internet, native email applications are usually used in conjunction with larger enterprise mobile email deployments. For example, here are two possible solutions:

1. Native email application and Nokia Business Center
   Combining a native email application with the Nokia Business Center allows enterprises to more securely extend their internal email servers to the firewall’s DMZ via an IMAP proxy and enables you to:
   
   • Gain email access via the native email application; with a better user experience and reduced mobile data charges
   • View common office attachments that are reformatted for mobile devices in circumstances where the relevant document viewer is not available on the mobile device.
2. Native email application and Nokia Mobile VPN
   Combining a native email application with the Nokia Mobile VPN solution on compatible devices allows a secure tunnel to be created between the mobile device and the corporate network. The native email application can then connect to the corporate email server as if it were on the corporate network.

What are the benefits?

• Client-server email systems allow you to read email even when Internet connectivity is not available - so long as messages have been downloaded. Similarly, email to be sent can be queued until your mobile device is online.
• The standard Internet email protocols used by email clients built into some Nokia business devices mean that they will work with most enterprise and ISP email servers.
• Blackberry email connectivity support in Nokia business devices allows enterprises with Blackberry investments to extend Blackberry usage to more employees in a cost effective manner.