A technique used by some electronic mailing list software (including SITEFORUM) to enable automatic detection and removal of undeliverable e-mail addresses. It works by using a different return path (also called "envelope sender") for each recipient of a message.
There is a full description of VERP on Wikipedia:http://en.wikipedia.org/wiki/Variable_envelope_return_path
SITEFORUM recommends the use of VERP to all its Software-as-a-Service clients. Especially the ones that use the SITEFORUM campaign manager to send out mass-emails to its users. VERP helps to:
- keep recipient lists clean
- send email only to people that can be reached
- get a better ranking at major email providers such as Gmail, Hotmail, Yahoo
The process is simple: If an email cannot be delivered to a recipient it will bounce back to the SITEFORUM servers. Once bounced it will be placed on a bounce list. If this happens for 3 times the recipient will be automatically added to the blacklist.
SITEFORUM has a list of configurable parameters that will be set by SITEFORUM administrators:
/bounce/blacklist/release_days Defines when emails that bounced before are removed from the bounce list. Default value is 30 days.
/bounce/blacklist/max_failed Describes how often an email address may bounce until it gets placed on the blacklist. Default value is 3.
There is no change in the SITEFORUM frontend. Bounces are still visible in the SITEFORUM Bounce Manager . Every bounce – no matter if a user reply, auto reply or real bounce - will be put on a bounce list. If limits are met or exceeded then the recipients email address will be put on the blacklist automatically.
Important: Once a “blacklisted” user logs into the system he/she will be presented with a red dialog that explains to them that the system couldn’t reach using the email listed in their profile. The user can then update the profile and also remove himself from the blacklist.
If your bounce email boxes are not managed by SITEFORUM Cloud Computing service then you need to check your mail server documentation. SITEFORUM’s email infrastructure can be activated this way and no "Catchall mailbox” must be created.
"User replies" include "Out of office" etc. will be ignored by the VERP process and can be manually processed.
The "VERP" overview also has the option now to see the logfile of which users have been moved to the blacklist. This allows you to monitor these critical decisions. You could also de-activate the "move to blacklist" box for the beginning so that you just follow how the system classifies things.
If users become blacklisted then we will remove them from the bounce list as well. The bounce show only mails that were not automatically processed by VERP ... such as challenge replies, user replies, out of office etc.
- Enable VERP => switch on/off
- Move bounced emails to blacklist => bounced mails, that meets the criteria will be added to the blacklist
- How many failed attempts => if there are more than these bounces, we'll move the recipient to the blacklist
- Release after days => This one is tricky. Sending a mail is noted. Getting a bounce mail too. If send count is higher than bounce count for more than x days the mail is release from the list. (We got no bounce in this amount of time).
Bounce VERP delimiters are used by SITEFORUM and mail server to identify the address of the recipient. There has to be no change, if the mail server setting is not changed as well.
The VERP listing is able to show up just the recipients, that will get on blacklist within the next run. If an address is temporarily on the bounce list, it will be removed if the next email delivery is successful.
We didn't sort out user replies properly, which should do better now.
An email address has to bounce 3 subsequent times within 30 days until it gets blacklisted.
Once an email bounced  sub-sequent times within  days it will be moved to the blacklist automatically and you can follow the processin the frontend we built you and you can see how many addresses it moved to the blacklist automatically.