Free Push Email for Windows Mobile

Wished you could provide Blackberry like push E-mail funcionality to your mobile users, but don't want to spent a penny? Z-Push is an Open Source push technology software that let's you do just that

Saturday, July 05, 2008

What is “Push E-mail”? You may have heard about this term frequently along with Blackberry or Microsoft Exchange. To put it simply, Push E-mail can be explained in analogy to SMS (Short Text Message) – the text message that you send using your mobile phones.

Whenever you send a SMS to someone, the recipient receives it instantly. Similarly, when someone sends you a SMS you receive it within seconds (if we assume a healthy cellular network). Compare this with the traditional E-mail, the non-push email.

You receive an E-mail when you click on the send/receive button in your E-mail client software (Outlook, Thunderbird, Pocket Outlook in Windows Mobile). This kind of retrieval of E-mail is called Pull.

But if an E-mail can also come as instantly as a SMS or without you hitting the receive button, that's what is a push E-mail.

How come you are able to receive a SMS instantly? Because your phone is always connected to the cellular network.

Very similarly, in case of Push E-mail, the E-mail client is always connected to the E-mail server.

The E-mail server notifies or sends the new E-mail(s) to the already connected E-mail client, whenever the former receives one.

This is true in case of Blackberry services or MS Exchange or whichever service/server/product that offers push e-mail.

Therefore one of the benefit of push E-mail is the same as that of SMS – that is, timely notification without your intervention. Another benefit is reduced battery consumption over POPing mails every minute (say).

Is it that, to reap the benefits of push E-mail you need to have an Exchange or Blackberry service ? The answer is 'no'. There are alternatives.

One of them is Z-Push which is a free and open source solution to set up push mail with your existing E-mail server.

Z-Push works specifically with mobile phones/PDAs which support ActiveSync. ActiveSync is the de-facto application for Windows based mobile phones to retrieve E-mails, contacts, calendar, etc.

On one end, Z-Push emulates an Exchange server. That is, the mobile phone or the ActiveSync application sees it as an Exchange server.

On the other end, Z-Push can connect to a “backend” to retrieve the data (i.e. E-mails in our case) and push it to the mobile.

For E-mails, Z-Push can connect to any E-mail server (the backend) which supports IMAP. It can be any mail server running on Windows or Linux.

In this article we will setup Z-Push on a RedHat based distribution like PCQLinux 2008 (www.pcqlinux.org), CentOS (www.centos.org) or Fedora (http://fedoraproject.org/).

The prerequisites
We will first setup Z-Push on a Linux server (say services.abc.com). To run Z-Push on Linux you will need to install Apache web server and PHP web scripting engine. On a PCQLinux, RedHat or Fedora distribution this can be done via issuing the following:

yum install httpd
yum install php

Since Z-Push will pick up mail from an IMAP server, you would also need to install the IMAP module for PHP, which can be done as follows:

yum install php-imap

After installation, you can start the web server as:

service httpd restart

For a mobile device to connect to this server, you will need to assign a public IP for the server. That is make the server accessible through the Internet. If your mobile device has WiFi capabilities, then you can still have a private IP for the server and test the setup within your LAN.

Download and Setup Z-Push
Download the tar.gz archive of Z-Push from http://z-push.sourceforge. net. Following is the direct URL to download the latest version (1.1.1) of Z-Push, as of writing this article:

http://download.berlios.de/z-push/z-push-1.1.1.tar.gz

After download, extract the archive into /var/www/html as:

tar -zxvf z-push-1.1.1.tar.gz -C /var/www/html/

This will create a directory named z-push under /var/www/html. Change to this directory (cd /var/www/html/z-push) and issue the following command:

chown -R apache.apache state

The “state” subdirectory is required to be writable by the web server. The above command sets up the same.

Next type in the following lines in a text editor (joe, vi, gedit or kedit):

Alias /Microsoft-Server-ActiveSync /var/www/html/z-push/index.php

php_flag magic_quotes_gpc off

php_flag register_globals off

php_flag magic_quotes_runtime off

php_flag short_open_tag on

Save the above in a file called z-push.conf in the directory /etc/httpd/conf.d. Next issue the following for the above settings to take affect:

service httpd reload

Configure Z-Push
We'll assume that you are running an IMAP mail server at mail.abc.com and your E-mail domain is abc.com.

As assumed above, the server running Z-Push is services.abc.com. Throughout the article, you will need to substitute these with the actual server and domain.

As a note, you can run Z-Push on the same server – the one running the mail server.

Open the file named config.php (found in the directory /var/www/html/z-push) in a text editor. Find the line which says:

if (function_exists("date_default_timezone_set")){
date_default_timezone_set("Europe/Amsterdam");

Substitute Europe/Amsterdam with Asia/Calcutta (or Asia/Kolkata if you are using Fedora 9). This sets the timezone.

We are setting it to IST (Indian Standard Time) by specifying Asia/Calcutta.

Next, find the line which says:

$BACKEND_PROVIDER = "BackendICS";
and change it to:

$BACKEND_PROVIDER = "BackendIMAP";

This specifies that Z-Push will be connecting to an IMAP server to push the data (E-mails).

We will now need to specify the parameters (hostname, username and password) for Z-Push to connect to the IMAP server.

Find the line which says:

define('IMAP_SERVER', 'localhost');

And change it to:

define('IMAP_SERVER', 'mail.abc.com');

As per our assumption mail.abc.com is your mail server. Next change:

define('IMAP_DEFAULTFROM', '');

to:

define('IMAP_DEFAULTFROM', '@abc.com');

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