XF 2.2 Email Bounce: do I have to choose PHP or SMTP?

[Lorthirk]

Hey there, sorry for the silly question, but I can't understand the wording used in the "Bounced email address" option. It says:

Note that this option may not work unless the return path parameter is enabled or mail is sent via SMTP using the Email Transport option.

I can't understand if:
- it "may not work, unless the return path parameter is enabled or mail is sent via SMTP using the Email Transport option"
OR
- it "may not work unless the return path parameter is enabled, or mail is sent via SMTP using the Email Transport option"

In other words, which is the transport mode that is compatible with bouncing?

 

[Kirby]

In other words, which is the transport mode that is compatible with bouncing?

Both transports can be used, but sendmail / PHP may (or may not, totally depends on the setup) require to set Return-Path via the -f parameter; SMTP will always work.