ACTIVE E-MAIL FILTER WITH CHALLENGE-RESPONSE

• US 20150180812A1
• Filed: 03/03/2015
• Published: 06/25/2015
• Est. Priority Date: 07/16/2002
• Status: Active Grant

• Current Assignee: Quest Software, Inc.
• Original Assignee: SonicWALL, Inc. (SonicWall Holdings Ltd.)
• Inventors: Wilson, Brian
• Granted Patent: US 9,503,406 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06Q 10/107 Computer-aided management of electronic mailing [e-mailing]
• CPC Class Codes: H04L 51/212 using filtering or selective blocking
• CPC Class Codes: H04L 51/42 Mailbox-related aspects, e.g. synchronisation of mailboxes

Abstract

When a user receives potential junk e-mail from an unknown sender address, an active filter installed in or cooperating with the user'"'"'s e-mail system sends a challenge e-mail back to the sender address. Unless the user receives a correct response e-mail from the sender address and/or a response that meets formal criteria, the active filter rejects the original e-mail and blocks future e-mail from that sender address. The challenge preferably includes a question that the sender must correctly answer in his response. The question is such that only humans can interpret and respond to it correctly. For example, the question may relate to and/or be incorporated in an image in the challenge. Lists of approved and blocked sender addresses are compiled. The user may directly enter addresses in the address lists. Addresses to which the user has sent e-mail may also be included directly in the approved list.

Claims

1. A method for filtering electronic mail (e-mail) at a central e-mail server comprising:

receiving an e-mail at the central e-mail server, the e-mail having a sender and a recipient;

sending a challenge message to the sender of the e-mail received by the central e-mail server in response to receiving an email,

polling, for a pre-determined period of time, for a response message from the sender in response to the challenge message, wherein the response message addresses the challenge message sent by the central e-mail server;

determining that a response message has been received from the sender;

evaluating the response message to determine a classification of the e-mail and sender; and

transmitting, the received e-mail to the recipient, including the information about the e-mail and the sender, wherein the recipient can store the e-mail and provide a label for the sender based on the information about the e-mail and the sender transmitted from the central e-mail server.

2. The method according to claim 1, wherein the classification for the email and the sender can be unwelcome and blocked.

3. The method according to claim 1, wherein the classification for the email and the sender can be welcome and approved.