Because COMBELL pays great attention to the accessibility of your mailbox, we have designed an advanced redundant e-mail network.

How do most hosting providers work?

Step 1: When sending out an e-mail, your internet provider is looking for the location of the receiver’s mail server. Therefore, he sends a request to the DNS server of the receiver’s domain name. Step 2: The DNS servers give the MX records of the receiver’s domain name as an answer. Step 3: The outgoing mail server of your internet provider does now know to which mail server he has to deliver the sent mail.

How does COMBELL work?

	Step 1: When an e-mail is sent out, your internet provider is looking for the location of the receiver’s mail server. Therefore, he sends a request to the DNS server of the receiver’s domain name.
	Step 2: The DNS servers give the MX records of the receiver’s domain name as an answer.
	Step 3: The outgoing mail server of your internet provider does now know to which mail server he has to deliver the sent mail: the e-mail is sent to the COMBELL “Mail distributor server”. This server is dividing all incoming e-mails over different spam- and anti virus filtering servers (load balancing). This includes saving the e-mail messages in case the filtering servers are not able to process everything at the same time (failover).
	Step 4: The e-mail messages are scanned for viruses and spam according to different criteria (see below) by several spam and anti virus filtering servers.
	Step 5: Once the e-mail is filtered, it will be delivered to your mail server or mailbox.
	Step 6: If the COMBELL Mail Distributor Server or the complete COMBELL network in Brussels is not available, e-mails are automatically forwarded to and saved at the COMBELL backup network in Antwerp at the backup Mail Distributor Server.
	Step 7: As soon as the COMBELL network in Brussels and the spam and anti virus filtering servers are available again, all e-mail messages are forwarded to the filtering servers in order to get processed.

ADVANTAGE: Via the implementation of a unique combination of technologies, COMBELL makes sure that all e-mail messages are delivered safely and are filtered for viruses and spam. This way we can guarantee that only clean messages will reach your mailbox. Even in emergency situations none of your e-mails will get lost, thanks to the many redundant servers.

The technology mentioned above is included in each COMBELL package for free!

Which criteria or methodology is being used by our filtering systems for scanning your e-mails?

Anti-virus scanner

The anti virus system is a dual layer scanner. Each e-mail is scanned by 2 virus scanners. This way we guarantee an optimal protection. Each hour, un update of the latest virus definitions is downloaded so we can keep a close track of the latest virus outbursts.

Anti-spam scanner

Blocking spam (unwanted e-mails) is done based on following criteria:

• Control via official “blacklists”: generally, several lists of servers are saved at the Internet, from where a lot of spam is being sent. COMBELL uses the blacklists of “spamhaus.org” for this. E-mails coming from these black lists are automatically deleted and will not reach your mail server.
  
  
• Bayes’ filter: spam is being recognised via the Bayes’ algorithm, via an extremely advanced and intelligent system, calculating certain patterns. This filter is completely trained by COMBELL based on a number of existing spam messages. The content of each e-mail is being analysed and gets a certain spam-value. If the value is higher than 5, the e-mail will automatically be deleted and will not reach your mail server. If the value is higher than 3, the e-mail will be forwarded to your mail server anyhow, including a spam-alert in the subject bar.
  
  
• Checksum technology: herewith, we check how many times a certain word or e-mail message reaches our mail server. If a certain number is exceeded, the e-mail will be recognised as spam. The system has a database of frequently used words in already registered spam.
  
  
• Checking message authenticity: via certain algorithms, we can filter the authenticity of a message. We check for example whether the sender of the message really exists.
  
  
• Rate control: recognition of DOS attacks and “dictionary spam”-attacks, spam you receive in large amounts.
  
  
• Furthermore, our software deliverer updates our software on a daily basis. This way, we can guarantee you that COMBELL keeps a close track of the most recent developments.

Summarised: what does all this mean?

COMBELL automatically scans your e-mails for viruses. If an e-mail contains a virus, the message will automatically be removed. If an e-mail meets the spam criteria mentioned above, than the message will be blocked. If the system is not 100% sure whether it is spam or not, the message will be forwarded to your mail server, including the word SPAM.

Can e-mail messages get lost?

In case the system should block an e-mail message because it’s recognised as spam, but you wish to receive it anyway, than we can still forward it to you. All messages are saved for 2 days in our filtering system.

Can I have the virus/spam filter turned off?

Yes, you can. The advanced mail filters will standard be included with each hosting package. But you can have it turned off, by sending an e-mail to our support department. This way, all e-mail messages will be sent to your mailbox unfiltered.