TechTip: PHP Delivers mail() on IBM System i PDF Print E-mail
Tips & Techniques - Web Languages
Written by Alan Seiden   
Thursday, 05 October 2006 18:00

PHP, the popular Web development language, has long provided a built-in function, mail(), to send email messages. Until recently, this function was available only on non-System i platforms. The limitation applied both to home-grown System i PHP versions and to beta releases of Zend Core for i5/OS (the PHP distribution by IBM and Zend).

Users of PHP on System i can now rejoice. The GA release of Zend Core for i5/OS, introduced in August 2006, implements mail().

Why Is mail() Necessary?

Although alternatives such as PHPMailer provide ample features, these substitutes take more effort to set up. More important, some software packages are programmed to use mail() and will not operate without it.

Implementation on System i

Most UNIX systems contain a sendmail program. The mail() function takes advantage of this by sending messages through sendmail. On systems lacking sendmail, such as Windows and System i, Simple Mail Transfer Protocol (SMTP) does the job.

Function Definition and Example

The mail() function takes four parameters:

  • To—Recipient's address
  • Subject—Subject of the message
  • Message—Message body
  • Headers—Optional catch-all parameter, responsible for most other message settings, including the sender's email address ("From:") and any special encoding. When messages contain attachments or HTML, this parameter can become complex.

All four parameters are shown in this short PHP program:


PHP.INI contains default mail settings. It can be found at /usr/local/zend/Core/etc/php.ini.

PHP.INI has three mail settings:

  • SMTP—Name of an SMTP server, such as System i's included SMTP service, to send mail through (e.g.,
  • smtp_port—Port number used by SMTP server (default: 25)
  • Sendmail_from (optional)—Default "from" email address to use when mail()'s "headers" parameter does not specify one. Any address can be used. The server does not check its validity (e.g., Note: Although messages are not required to be "from' anyone, messages lacking a "from" address may be seen as spam.

The three settings appear in PHP.INI under [mail function] like this:

[mail function]
smtp_port = 25
sendmail_from =

To change these settings, either edit the INI directly or use Zend Core's Web-based administration console.

The EDTF (Edit File) command allows editing of PHP.INI from a command line:
EDTF /usr/local/zend/Core/etc/php.ini

A PC-based text editor will also work, given adequate authority to PHP.INI.

Zend Core provides a Web-based control panel to edit these settings, located at (where is the appropriate domain name) on the PHP Configuration page (Figure 1).

Figure 1: The PHP Configuration page allows editing of sendmail_from, SMTP, and smtp_port. (Click image to enlarge.)

Changes to PHP.INI will take effect after the Apache server is restarted. Apache can be restarted with the Restart Server link in the Web interface and with Zend Core's Apache menu: GO ZENDCORE/ZCAMENU.

Set Options Dynamically with ini_set()

PHP's ini_set() function temporarily sets a given configuration option. Ideal for altering options dynamically, and in installations unable to change PHP.INI, ini_set() affects options for the duration of the program that invoked it.

ini_set() takes two parameters:

  • VarnameVariable/option to change
  • Newvalue—Value to change to

The following lines of code show how to set the SMTP server and "from" address within a PHP function.
ini_set("SMTP",""); // note: “SMTP” must be upper case.


If mail() does not work as expected, clues may be found in PHP's error log:

The error log may be viewed with a text editor or this command:
DSPF '/usr/local/zend/Core/logs/php_error_log'

mail() vs. Alternatives

As mentioned earlier, mail() is not the only way to send mail in PHP. Fuller-featured alternatives include the following:

PHP Extension and Application Repository (PEAR) Mail (recommended by the official mail() function page for sending HTML or complex emails)

Advantages of mail():

  • It's included with PHP; no installation and little configuration needed.
  • One line of code is sufficient to send a simple message.
  • Many prominent software packages, such as WordPress blog software, depend on mail(), which is not an advantage per se, but it's a reason to have it available.

Advantages of the alternatives:

  • Support for SMTP authentication, which is absent in mail(). In SMTP authentication, a mail client proves its identity to an SMTP server with a user ID and password. Many SMTP servers, such as Lotus Domino's, can be configured to demand authentication to deter unauthorized use.
  • Programmers need not understand mail headers. Complex messages and attachments are handled easily, without complicated header strings.

An Invaluable Tool

The mail() function works well for relatively simple email tasks. Its hidden strength, though, is in the many software packages that use it. With the GA release of Zend Core, System i gets the power to host an expanded universe of commercial and open-source applications written in PHP.

Security Considerations for mail()
Zend Brings PHP to IBM's i5/OS (article by this author; introduction to PHP on System i)
Main page, Zend for i5/OS

Alan Seiden
About the Author:

Alan Seiden, an authority on PHP development with IBM i, helps his clients achieve best practices and top performance when combining PHP, Zend Framework, IBM i, RPG, and DB2. He was one of the first Zend Framework certified engineers, later co-founding the NYC Zend Framework Meetup. Alan was a charter member of IBM/COMMON's PHP Advisory Board and a consultant for IBM's manual PHP: Zend Core for i5/OS. An award-winning speaker, Alan is project manager of Zend's open-source PHP Toolkit for IBM i and a Zend Reseller Partner. As a certified Feldenkrais practitioner, Alan also gives workshops on reducing the physical stress of computing. Contact him at Alan Seiden Consulting, Ho-Ho-Kus, N.J., | | @alanseiden

Last Updated on Wednesday, 17 September 2014 09:29
User Rating: / 0



See What i Can Do With Modern RPG Development

Your applications deserve more than just a new look! Change the perception of the IBM i as “old” with modern development tips from IBM and Profound Logic Software.
Watch as Barbara Morris, Brian May and Alex Roytman dive beneath the GUI surface to show the benefits of:


  • Working with free-format RPG in IBM i TR7
  • Breaking free from “The Cycle” of traditional RPG development
  • Going beyond the 10 character limit in display and database files
  • And more!

You'll also see a live demonstration of these techniques as the presenters create a modern web application before your eyes! 


Watch the Webinar Now!



MS Office Connector for Query/400

NGS' Qport Office enables Windows users to run IBM Query/400 queries to: 

 - Create and update Excel spreadsheets and Access databases

 - Create Word documents

 - Send to Windows screen and PC printers

No query conversion is required. Works with i5/OS V5R1 & above. Installs in minutes!

If you don’t have a budget to replace IBM Query/400, but want your users to have one click enhanced output of their queries.… Request the online license agreement and product download instructions today!

Offer good through December 31, 2013.