Spam Checking
Spam detection
We employ various techniques to reduce the amount of spam email we accept for domains that we host email services for.
This page will outline the main systems we have.
Initial connection - Block-listed IP addresses
One of our first line of defences is using the Spamhaus block lists to deny access from IP addresses that are listed by Spamhaus.
Two Spam Engines
Since October 2023 we use two spam checking engines: (previous to this we only used Spamassassin)
- Spamassassin
- Rspamd.
Both of these will assign a 'spam score' to the message. We will then use the highest score to classify a message as spam or not.
Spam score options
Once a message has been processed by the spam engines the message will then be subject to one of three options:
- Non-spam - accept
- Medium-scoring Spam - accept, but marked with ***SPAM <score>*** to the subject, and saved to the spam folder
- High=scoring spam - rejected
The score at which a messages is marked as spam or rejected can be set on the Control Pages on a per-Mailbox or per-Domain basis. The default score to mark as spam is 5, and to reject is 20.
Headers
We do add various extra headers to email regarding the Spamassassin and Rspamd scores and reports.