Mail routing terms
- MX record: the DNS record that tells other mail servers where to deliver mail for your domain. Pointing it at SpamDuster sends your incoming mail through the filter.
- Mail host (MX target): your SpamDuster server's hostname, which your MX records point at.
- Destination mail server: your own mail server, where SpamDuster delivers clean mail.
- Time-to-live (TTL): how long other servers may remember a DNS record before checking it again.
- Relay: a mail server passing a message on to another server.
Filtering terms
- Spam score: the total of the points a message collects from the checks it fails. A message whose score reaches the limit is blocked as spam.
- Greylisting: asking a sending server SpamDuster has not seen before to try again a few minutes later. Real mail servers retry; many spam tools do not.
- Blocklist: a public list of IP addresses or domains known to send spam.
- Phishing: mail that tries to steal passwords or money by pretending to come from someone you trust.
- SpamDuster PhishList: our list of known phishing links, updated continuously, that every SpamDuster server checks links against.
- False positive: wanted mail that was blocked. False negative: spam that was delivered.
Sender authentication terms
- SPF: a DNS record listing the servers allowed to send mail for a domain.
- DKIM: a signature added to a message by the sending domain, which proves the message was not changed on the way.
- DMARC: a domain's instruction on what to do with mail that fails SPF and DKIM for that domain.
Console terms
- Release: delivering a copy of a blocked message to its recipients.
- Not spam / Mark spam: corrections that teach the filter.
- Allowed sender: a sender whose mail skips the spam and phishing checks for one of your domains or mailboxes.
- Discarded: spam kept out of the filter's learning, such as floods of identical spam.
Updated 2026-10-26Need help? Open a ticket in the billing portal.