The way the system works is by running a variety of tests and assigning a value for each respective test. All tests that the email fail will be listed in the header of the email. Once an E-mail fails enough tests to reach a certain "trigger" value, we will mark the email as spam. The recipient then can decide to read or delete the email.
- MAPS RBL - This used to be the most popular test, used by many large Internet Service Providers. It tries to block sources that allow spam to be sent through their servers, and do nothing to prevent it. It now requires a subscription from mail-abuse.org.
- Envelope Mail From - This tests the "From" address as listed in the SMTP envelope, to make sure that the domain has an MX or A record. Or, if you want to be super strict, you can just check the MX record.
- MAPS DUL - DUL has a list of many "dial-up lines", or IP addresses of people connecting with a modem. Most spammers use a dial-up connection to connect to an innocent mail server (possibly yours!) to do the dirty work. This doesn't trap much legitimate email, since those usually will go through a real mail server. It now requires a subscription from mail-abuse.org.
- OSRSS - OsiruSofts Open Relay Spam Stopper. Another list of spammers' IP addresses. Includes 5 different databases.
- Reverse DNS - Checks to make sure that a reverse DNS entry exists for the IP address sending you the mail. The RFCs require a reverse DNS entry, and lots of spam is sent from IPs without a reverse DNS entry. However, there are quite a few legitimate mail servers set up without a reverse DNS entry.
- NOPOSTMASTERS - This database lists domains that do not have a postmaster address (which violates RFCs).
- NOABUSE - This database lists domains that do not have an abuse address, which also is required.
- DSN - You can use this database to handle email coming from domains that block bounce messages (which can cause you extra work).
- BADHEADERS - Looks for broken email headers, which are common in spam as spammers try to forge headers. This test can't accidentally catch any legitimate mail (except mail from broken email clients, probably beta versions).
- SPAMROUTING - Looks for email that takes a very poorly defined path that wastes bandwidth. For example, a U.S. spammer sending to a recipient in the U.S., but relaying through a server in China would trigger this test.
- Other tests we may be using see ip4r DNS lookup list.
We offer virus protection at our email server -- meaning we scan your incoming email BEFORE it reaches your computer. With email being the most prevalent way viruses are spread, our virus 'firewall' provides you with a front line defense against known virus attacks.
Some of our email scanning features are:
- Notification. Upon a virus detection we send the a message to the sender, recipient,and others notifying them of the infection - in an attempt to further protect all interested parties.
- Up to date definitions. New virus definitions are loaded daily or as new definitions become available.
- Virus scanning is optional. If you do not want scanning it can be disabled.
- Viruses are deleted. Emails that contain viruses and even emails that are viruses themselves are not delivered - they are deleted.
- We scans attachments, as well as non-text segments of E-mail. It's important to scan non-text segments, such as HTML, because they can carry viruses/worms just as easily as attachments can.
- ALL email is scanned.
- Sender Notifications are tured OFF for viruses that can forge the sender.
We use the most state of the art virus detections systems available to us however there is always the chance of a virus slipping through, typically one that is a new and undiscovered in the wild. We offer a very stout front line defense and it should compliment - not replace - your own virus protection system. We make no warranty of any kind - expressed or implied that we can protect your computer from all viruses nor are we responsible for any damages consequential or otherwise that a virus may cause.