May I ask what is the bounce email under "General setting" ? Is this the email address where bounced emails will be sent to ?
If i do not use limesurvey to blast survey invitation, I could ignore this field, right?

Thanks in advance!!

The bounce email is important if you want to automate the bounced email processing via Limesurvey.

So if you would send out emails via Limesurvey and they bounce, Limesurvey can automatically recognize this and work with this information. If you send your emails with another tool, this most probably will not give you any advantage and you could ignore it. Let's see if someone elese who uses the email feature more has some further information.

holch wrote: If you send your emails with another tool, this most probably will not give you any advantage and you could ignore it.

The bounce mailaddress is very often needed, when using the sendmail/phpmail method (better choose SMTP!).
When sending via sendmail/phpmail over the webserver, the bounces would mostly come back to a system administrator account, instead of the From address. I recommend to set the bounce address to the From address, if you don't have an dedicated bounce emailaddress.

Just for reference, here the code:
github.com/LimeSurvey/LimeSurvey/blob/ma.../tokens.php#L69-L272

When using an external SMTP server, the bounce information must be handled outside of limesurvey? So if I use and external smtp server I must manually update the tokens tabel with bounce information? Is that correct?

Sincerely

No. You need an email account that received the return messages and Limesurvey needs access to this email account.

So you need an IMAP or POP3 account to receive the bounce emails:
www.limesurvey.org/manual/Email_bounce_tracking_system