How does it work
Typically a server that utilizes greylisting technology generates triple data for each arriving email message:
- Sender IP
- Email address of the sender
- Email address of the recipient
This triple data is then verified with the triplet registered in the database. If this triplet has not yet been registered, the sender is placed in the greylist for 10 minutes and the incoming emails coming from it are deferred (delayed with a "retry later" response).
The Greylisting is efficient because spammers tools usually don't try to resend an email. If the spammer tries to resend the email, LibraCyber ESG will accept it and analyze it as usual via the antispam engine.
Note: the greylisting plugin is not enabled by default, you need to manually enable it.
Warning: this plugin may introduce significant delays to messages with some providers using a pool of servers to retry the delivery as they use different source IP addresses.
Greylisted Waiting
In the first tab are listed addresses that are waiting to pass the greylisting hold time. You can filter out the displayed records by performing a Search. You can delete one or more addresses by selecting them and clicking the Delete button on the table toolbar.
Auto Welcomelisted Emails
In this tab are displayed addresses that have passed the greylist tests and now are trusted. You can filter out the displayed records by performing a Search. You can delete one or more addresses by selecting them and clicking the Delete button on the table toolbar.
Auto Welcomelisted Domains
In this tab are displayed domains that have passed the greylist tests and now are trusted. You can filter out the displayed records by performing a Search. You can delete one or more domains by selecting them and clicking the Delete button on the table toolbar.
Custom Rules
In this tab you can manually put email addresses and domains in welcomelist. All the messages coming from these domains and addresses will not wait the greylisting hold time. You can also manually put email addresses and domains in the greylist. All the messages coming from these domains and addresses will always wait the greylisting hold time.