Anti-Spam and Anti-Virus

Netservers' email platform has flexible user-configurable anti-virus and anti-spam system. Rather than relying on just one spam detection solution, we use a variety of different spam detection tools and strategies.

Using our web-based control panel you can:

  • Choose your own spam detection threshold
  • Opt in or out of Sender Address Verification
  • Whitelist your contacts and associates
  • Blacklist persistent spammers

The setting can be done on both a per-user and per-domain basis.

Spam score thresholds

The core anti-spam software used by Netservers is SpamAssassin (SA). Using a variety of tests, SA assigns a scores to each email it sees, indicating the likelihood that that email is spam. An email with a score of 8.00 or more is almost certainly spam and is immediately rejected. Emails with scores between 5.00 and 8.00 are probably spam.  In practice the vast majority of spam has a score of 20 or more, so only a small minority fall into this questionable category.

You can control the spam score threshold (default 5.00) through our web-based control panel. By default, our servers mark emails with a score of between 5.00 and 7.99 as spam in the subject line. We also add headers indicating the score in the email headers. This email tagging can be used by your email client to route your incoming email in to a "junk" or "spam" folder.

Sender Address Verification

Many spammers generate bogus email addresses for the supposed sender of their emails. By default, Netservers' mail servers check the validity of the senders address for each incoming email. If we positively confirm that the senders email address does not address, we reject the email.

However, some genuine web sites (in violation of internet rules) send emails from non-existent email addresses. You can still receive these emails by whitelisting the senders address or domain name. Alternatively, you can turn Sender Address Verification off entirely on either a per-user or per-domain basis.

Whitelists and Blacklists

Each domain and user gets their own whitelist and blacklist. Any email address or domain that is whitelisted bypasses all anti-spam or sender address verification checks. Any email where the sender's address or domain blacklisted is rejected before any other checks are carried out. All of this is under your direct control via our web-based control panel.