I have an old email address that I don't use any more, say
firstname.lastname@example.org. This address gets loads of spam, but also the occasional email from an old friend. I have set up a new address, say
email@example.com, that I would like all my friends (but not the spammers!) to use.
I will of course send the new address to everyone I can think of, but I'm sure to forget some. How can I tell the humans who write to
firstname.lastname@example.org, while telling the spammers to go away?
One method I thought of is to auto-respond to every email to
email@example.com with a reference to a website with a CAPTCHA on it; only if you answer the CAPTCHA do you get advised to resend your email to
firstname.lastname@example.org. (One problem with this method is that I'm not sure how to set up the auto-response effectively - if there is a lot of spam, I could use up all my bandwidth responding to spammers again and again.)
Both emails are currently administered by my ISP's mailserver, but I own both example.com and example.org and have a server where I can install software (e.g. a web or mailserver), so I could set up either address to use whatever method is needed. Of course, I'd like a solution that requires the least maintenance possible.