Multi-Layer Anti-Spam

Multi-Layer Anti-Spam

The Network Box Anti-Spam solution is the most comprehensive and effective gateway Anti-Spam solution in the market today. It provides 25 Anti-Spam engines, combining over a dozen different techniques and is backed by a vast database of Anti-Spam signatures. It provides true defence-in-depth, in a single managed gateway appliance.

The Network Box Anti Spam email gateway achieves an industry-record 97.5% detection rate, with almost zero
false-positives.

 

Some of the solutions deployed by Network Box are:       

  • Co-operative Spam Checksums
    This technique involves breaking apart a message and taking cryptographic checksums of each component of the message. 
  • Signatures and Spam Scoring
    Lists of ‘signatures’ which match aspects of spam messages.
  • White lists and Black lists
    A list of words / patterns which make a message ‘ham’ (good email) or ‘Spam’.
  • Heuristics
    By examining behaviour, tests can be designed to determine if an e-mail is Spam.
  • Real-Time IP Blacklists
    Lists of gateways known to be either:
    • known sources of Spam
    • known open-relays (allowing third-party relaying of messages)
    • known dial-up networks
  • Real-Time URL Blacklists
    Lists of URLs used by spammers
  • URL to IP Mapping and Blacklists
    Lists of IP addresses used by spammers
  • URL Categorisation
    Using the on-board SurfControl database, URLs can be categorised
  • Domain Age
    If a domain is very young this can be an indicator of Spam.
  • Bayesian Filtering
    Statistical (or Bayesian) filters can be used to automatically maintain word / pattern white lists and blacklists, together with statistical probabilities as to whether the given word / pattern makes the message spam / ham.
  • Challenge / Response Systems
    Network Box can challenge previously unknown senders to check they are not spammers.
  • Digital Signatures
    This technique is normally used to indicate that an email message is ‘ham’ and is not used to determine spam.
  • Optical Character Recognition (OCR)
    Spam sent as pictures can be interpreted as text and hence detected.

Anti-Spam Configuration

The Network Box email system is extremely configurable. Individual engines can be enabled or disabled based on tests, including:

  • Direction of the message (inbound or outbound)
  • Whether the message is being filtered (eg, POP3, IMAP4)
  • Whether the message is redirectable (eg, SMTP)
  • Globally (ie, for everything)
  • Based on the content of a message headers
  • Based on the proxy handling the message (eg, SMTP, POP3)
  • Based on a single recipient of the message
  • Based on a recipient being one of the recipients of the message
  • Based on the sender of the messages
  • Based on the sender IP address
  • Individual engine parameters can be set to adjust scores and weightings to suit end-user requirements.