The mail bounce tracking system (available in v1.91 or later) is capable of tracking down and marking the e-mails that were not delivered to the recipients (participants). The system relies on the "mail delivery notification failure report" and therefore need the administrator's e-mail address using which the e-mails were sent or a special account used only for tracking the bounces . Along with the address of the account, the credentials of the account are also required, with the connection details.
The php5-imap module must be installed on your server. You can check if this is the case, by looking at the show phpinfo button, found on the Global settings page.
Then look for an imap section, like this. If an imap section is shown, you are good to go:
If you don't have php5-imap installed, and you have root access to the server, your can install as per your distributions normal procedures. For e.g. Debian see this: http://www.electrictoolbox.com/install-php-imap-debian/ . Just remember to restart your web server, for example for run "apache/usr/sbin/apache2ctl restart"
The basic idea behind the development of the system was to reduce the manual work and reducing human errors in the way.
The basic working of this system is that when sending the mail, the mail bounce tracking system automatically adds an survey-id and token-id to the mail header without administrator notice.
These headers, also known as custom headers, are added to each invitation email that LimeSurvey sends to the participants.
When the mail is bounced back, the original header along with the Delivery notification header is received. The system then checks for new mails and parses the mails that have these custom headers and mark the wrong e-Mail id in the red font color in the tokens table.
The system is capable of working at the global level or survey level, thus the settings can be saved accordingly. The global settings can be saved under Global Settings -> Bounce Settings.
The local settings can be entered under the token management of that particular survey.
As you can see in the screenshot above the setting to be used in that particular survey is to be selected. Available options are
Once the settings have been set you can start the bounce processing by clicking on the bounce processing icon in the Token browser toolbar as shown below.
After clicking the icon you will be presented with a popup which shows a progress meter.
Wait for it to complete. Once complete the result of the scan will be shown and after a refresh of the browse responses page (you might have to do that manually) all the entries whose invitation are bounced their e-mail address are marked in red font. Also their "Email status" is chanced from "OK" to "bounced".