[Nottingham] Challenge-Response systems

Graeme Fowler graeme at graemef.net
Fri Nov 4 09:57:27 GMT 2005

On Fri 04 Nov 2005 09:28:21 GMT , Andy Brown <nlug at jester.nu> wrote:
> How do people feel about challenge-response systems as anti-spam measures?
> How about CR systems that require a graphical browser to confirm the email?

They work in certain cases, especially in cases where you really can be 
bothered (or in fact have to be) to complete the challenge. They've 
been around for years in their most basic form:

"Your email has been rejected as you're not in my list of accepted 
senders. Please click here [link to web page] and add your address 
there, then resend the message."

I know of a dozen or so people (5 of whom are German, oddly enough) who 
have used that approach for several years. The one-off nature of it 
means it's not too challenging (please excuse terrible punnery).

To have to do this for each and every email you send, however... I 
suppose in some tiny number of cases it might be bearable, but if (say) 
I was on a mobile phone I'd just want to be able to send a message and 
have it delivered rather than having to then fire up a browser.

I second Martin's comments about properly configured spam filtering. It 
isn't rocket science these days.


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