Environment
GWAVA 4 112+
All Supported OS
SMTP Scanner
Situation
What is the Conceal 5xx rejection option?
Resolution
If the Conceal 5xx rejection option is set to All, this will cause any server that sent mail that was blocked by the SMTP scanner to receive a 250 OK message, as though your system took it, instead of a 500 level message blocked message.
This can be useful in stopping spammers from getting a list of users via a dictionary attack. They can do that by comparing the blocked users with the received users.
By default the option is set to None, so if a mail was blocked by GWAVA the sender will always receive the "550 Message was blocked" message.
Additional Information
This article was originally published in the GWAVA knowledgebase as article ID 1077.