SpamHelp - the one-stop anti-spam resource
Home
Appliances
Articles
Books
Events
Services
challenge/response
disposable email
managed anti-spam
Software
client-based
server-based
miscellaneous
Harvester Killer
Network Tools Open Relay Test
Humor
Spam News
Submissions
Links
Contact Us



Linking to us

Challenge/Response Services

This is a list of email verification service (also known as challenge/response) providers. When an email arrives from an unknown sender, a reply email is sent back asking the sender to verify/authenticate either by simply clicking on a link, answering a simple question, typing in what can be seen in an image, typing in what can be heard in an audio file, or any other idea that these providers come up with.

Spam Arrest     [Listing added: 3 September 2003]
When an email arrives from an unknown sender, a reply email is sent back asking the sender to verify themselves by clicking on a link to the Spam Arrest website. The link takes them to a page where they are instructed to type in a word that is shown in a picture. This step prevents automated systems, such as those used to send spam, for authorizing themselves, yet is very easy for any human to complete. Unverified emails are stored on the Spam Arrest website for 7 days, and you may review them at any time. You may also allow pre-authorized senders and mailing lists at any time, either by entering them individually, or by uploading your entire address book.

Company:Spam Arrest, LLC
Screenshot:click here

SpamBlock     [Listing added: 20 May 2005]
SpamBlock is a FREE, hosted service that can eliminate spam originating from your website email addresses. There is no software to install, just some HTML to put in place of your email address mailto links on your website(s). The service is FREE to use and you can add as many email addresses or websites as you would like. SpamBlock uses a CAPTCHA challenge that is emailed back to the sender to veify the authenticity of their email.

Company:SupportSentry

SpamKilling AntiSpam     [Listing added: 15 May 2004]
SpamKilling AntiSpam is a software add-on to famous mail server - SendMail, it enables this mail server to block automated junk emails. When an email arrives from an unknown sender, AntiSpam sends a confirmation email back asking the sender to verify themselves by entering a Magic Word in a subject line of the replaying email. This step prevents automated systems, such as those used to send spam, for authorizing themselves, yet is very easy for any human to complete. Unverified emails are stored on the mailserver for some days, and you may review them at any time. You may also pre-authorize senders and mailing lists at any time, either by entering them individually, or by uploading your entire addresses database.

Company:Digital Products International Corp.

Source Authentication Enterprise Edition     [Listing added: 2 November 2003]
The Source Authentication Enterprise Edition product is available for IT managers who want the most effective spam-elimination technology available for Exchange Server. The software is compatible with Windows Server 2000 and 2003, and Exchange Server 2000 and 2003. This product comes with a system administrator tool to manage the setup and configuration giving you complete control. Our patent-pending technology authenticates the identity of email addresses sending messages through a process called "Source-Authentication". Source-Authentication authenticates the source of email messages through the sender's own source point where they are able to access mail. Anyone who sends you an email will have to reply (1 time) to an email message sent by Enterprise Edition to confirm that they are the account holder for an email message.

Company:Block All Spam, Inc.

Mail UnKnown     [Listing added: 19 October 2003]
Mail Unknown gives you the power to control the emails you receive. All incoming emails are put on hold until the original sender has verified as a real email account and requests your permission to send you email. You then validate them by Authorizing or Blocking them. If you block them, their emails are erased without you ever seeing them. If you authorize them to email you all emails past and future received from the sender will be delivered into your current email software or service.

Company:Matrix Productions, Inc.
Screenshot:click here

WithoutSpam     [Listing added: 12 October 2003]
WithoutSpam uses a combination of unique technology and a human touch to defeat the exponentially increasing problem of spam. WithoutSpam will save you time and money and end the frustration of receiving constant unwanted email. When a new message is sent to you, WithoutSpam checks to see if the sender is authorized to send you emails. If so, the email is placed in your inbox, with absolutely no delay. If the sender is blocked, the email is deleted immediately. If this is the first email from the sender, the email is held in a temporarily holding location and the sender is sent an email with a challenge which only a human is capable of completing. The sender only needs to complete the challenge once, and their email, and all future emails that they send you, will immediately be placed in your inbox. You may also explicitly approve and block senders at any time.

Company:WithoutSpam.com
Copyright © 2014 SpamHelp. All rights reserved.