On this page, you can find information about Opus One's anti-spam technology.

All mail entering Opus One from the Internet is scanned both for viruses and spam. Because most email we receive is spam (usually about 75%, although this number fluctuates over time), we employ dedicated anti-spam and anti-virus servers to handle messages before they enter our main email servers.

Opus One uses a reputation-based anti-spam service to pre-filter all mail coming into our servers. This means that certain email senders will not be accepted by Opus One, whether they are sending spam or regular mail. We have been using this technology for four years and have found it to have almost no false positives (less than five have been detected over the years we have been using it) and to dramatically reduce the amount of spam coming into the network.

Mail received by our scanners is first checked for viruses. Any messages with viruses are dropped from the mail stream. You can learn more about our anti-virus scanning here.

Next, messages are checked for spam. Our anti-spam scanner can mark a message as "definitely spam" or only as "suspected spam." Messages marked as definitely spam are dropped from the mail stream. Messages that are only suspected to be spam are forwarded on, but with the string [SUSPECTED SPAM] in the subject line of the message.

At this time, we do not have per-user settings or a quarantine of spam caught for each user.