Technical Information


Deployment of the TetherFilter appliance could not be easier:

  • Connect TetherFilter to your network
  • Power up and set the IP address via. the front panel LCD and keypad
  • Point your domain's MX record in the DNS to the TetherFilter's IP address - or -
  • Set the TetherFilter's IP address to the one used by your email server, and then change its address
  • Log into the web interface of the TetherFilter and enter your domain information
  • Congratulations, you are now stopping 98%+ of the spam entering your network!

TetherFilter ships with a solid set of spam filtering rules, so straight out of the box, without modification, it can begin stripping spam out of your incoming email flow while ensuring accurate delivery of legitimate business email


TetherFilter also allows system administrators and individual users, who are enabled by the system administrator, to define a sequence of rules to customize TetherFilter behavior. System Administrators can extend default behavior to look for inappropriate, confidential, or potentially dangerous electronic mail messages on the network. The open architecture defined in TetherFilter, gives system administrators the ability to dynamically change behavior when high priority emergencies emerge. And throughout the simple and clean web based interface, Tethernet has produced a compelling and powerful tool to remove unwanted mail from your e-mail server. There is no longer any excuse for unwanted electronic mail messages.

View screen shots of the TetherFilter web interface

End-User Administration

TetherFilter can accommodate simple 'zero-admin overhead' user management. Users automatically receive TetherFilter login information through their e-mail addresses and no account/password integration is necessary with existing corporate account management. TetherFilter users can view their own quarantined folders and can customize user specific message handling rules. The TetherFilter administrator can determine if quarantine messages are deleted, placed in the system quarantine or sent to the users quarantine folder. Quarantine folders can be viewed though the TetherFilter web interface. TetherFilter works within your corporate security philosophy when customizing access and handling of unwanted messages. Users can be prevented from accessing TetherFilter's interface or given greater access which reduces administration management headaches.

When TetherFilter first receives a message from the internet, that message is processed though the system global incoming rules. For most organizations, these will use the default TetherFilter rules. The default rules remove about 99% of unwanted spam. This spam, by default is placed in the system quarantine and not available for users to view. Administrators can, optionally, send the quarantined messages to the users quarantine folder. This will allow users to login to the TetherFilter web interface and view the quarantine messages. Users can,optionally, specify additional message handling rules. All user incoming rules are processed after the global system incoming rules.

Anti-Spam Engine

TetherFilter does not, by default, consider the content of a message to determine if it is unwanted bulk mail. Instead, it uses protocol and formatting rule violations to determine the nature of the message. The great majority of unwanted build mail violates these rules. As a result, TetherFilter is a safe product for doctors, engineers, lawyers and other professionals who routinely deal with content that mainstream anti-spam products will tag as pornographic mail. Accidental marking of legitimate mail is the number one cause of complaint by users of such products that mistakenly mark a legitimate message as undesirable pornographic commercial mail.

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