|License:||Open Source: BSD|
|Updated:||28 February 2015|
Check validity of recipients by contacting another mail server.
Remove invalid recipients. Refuse mails with no valid recipients.
Useful for filtering on intermediate relays that don't have a
complete list of all valid users.
A lot of spam doesn't carry valid recipients. Checking recipients
is much cheaper than full content analysis.
Hence, inserting this plugin into the chain before the expensive
content analysis plugins can greatly reduce the load on the filter.