Email Testing : Inbox Inspection and Spam Filtering

Inbox Inspection : It is a technique using which we can see the preview of our mail in various mail service providers without physically installing all the mail service providers in our machine.

Checklist for Inbox Inspection :

-Font types and sizes are showing up correctly in all major email clients.

-Hyperlinks are getting displayed properly.

-Proper line breaks are visible in all email clients.

-None of the content of the mail is getting missed in any of the email clients.

-No extra characters and contents are getting added on their own in any email clients.

There are web application which provides such services. One of them is https://www.litmus.com .

The first thought which comes to mind is which email clients should we test on? In order to get a rough idea, this chart might help us:

Web applications like https://www.litmus.com provides us the preview of our mail content in these major email clients with very nominal charges and plans. This type of web applications are easy to use and they have tutorials too which might be helpful if you are a new to email testing. Its upon our need which type of email client we need to test, it may be the following : 

Desktop Email Clients : Apple Mail, Lotus Notes, Outlook, Thunderbird.

Mobile Email Clients : Android, Blackberry, iOS, Symbian, Windows Mobile.

Web Based Email Clients : AOL Mail, Gmail, Hotmail, Me.com, Yahoo! Mail.

We need only to check the check boxes for which email clients we want the email testing to be done. Enter the content of your email > Run the test > You simply get the preview of your email in all the email clients you have selected. We can also generate screen shots of all the previews and save them in a zip format.

We can see the preview in all email clients by clicking on the respective screen shots. The preview are initially shown in forms of thumbnails which we can view by opening it in a separate tab.

Let's say you want to view your email in BlackBerry8900, then you just need to click on the second thumbnail and you will see something like this:

This is how we can easily inspect our mails in our respective email clients easily and effectively. Its quite Simple!!

Spam Filtering : It is a technique through which various spam filters decide which content of the mail is spam alike and on the basis of that, gives score to it. If the score is safe enough then we simply receive the mail, otherwise it is blocked assuming it as a SPAM.

The various SPAM filters which are used by most of the email clients are:

• Spam Assassin is a very popular open source spam filter. Spam filter scores out of 10. A score of below 6.3 is considered a pass ans it means its safe to have it in our inbox. This may vary at an organizational level.
• MessageLabs is an expensive corporate server side spam filter. It has its own scoring mechanism.
• Postini is another server-side spam filter now owned by Google. And there are many more spam filters.

Let's see some screen shots displaying the result of test run for SPAM filtering using some of the SPAM filters:

How SPAMS are filtered :

Like humans, the first thing which these spam filter does is checking the subject of the message if it contains some suspicious words. As an example, we can say that it might search for strings like

-Viagra, Porn, Buy Now, Free, Lowest Price, Click here etc.

-Flashy HTML like large fonts, blinking text, bright colors etc.

Many SPAM filters compare the amount of suspicious text to the total amount of text to make a good wise decision so that an entire 12 page papers won't gets blocked just because the filter found some suspicious words, strings and patterns.

How can we prevent our mail contents not getting marked as SPAM :

1. Try to minimize the use of large fonts, colored fonts and ALL CAPS including in your signatures. These might raise your spam score.
2. Try to use a bit descriptive subject so that it doesn't matches with the strings which SPAMMERS use like “very urgent” etc.
3. Try not to send attachments with following extensions: lnk, asd, hlp, ocx, reg, bat, chm, cmd, cpl, exe, dll, vxd, pif, scr, jse, shm, shb, shs, vbe, vbs, vbx, wsf, wsh, wmf etc.But if there is really a need of sending attachments with file type as one of these, then the best way is to archieve the file in a zip format and then attach it to your mail, this will surely help your email to reach to its destination crossing all the SPAM filters.

Hope It Helps ! 

Regards,

SK Srivastava