How do email receivers go about populating whitelists?
The whole strength of email is that you can hear from people you’ve never heard from before; new people outside your normal circle can talk to you. But the whole weakness of email is that you can hear from people that you’ve never heard from before; spammers can send you junk.
The weakness of using whitelists – and blocking the rest of the world – is the “introduction problem.” How do you hear from new people? They have important things to say to you, yet you aren’t listening to them and that is by design.
In reality, this problem has analogies in real life. Think back to your own experiences; when you first started out your working career, nobody would hire you because they wanted people with experience. But how are you supposed to get experience if nobody will hire you? Another example is when Homer Simpson wanted to join the Stonecutters, he was stonewalled because to get into the club, you had to either be related to an existing member, or save the life of an existing member. Since the Stonecutters wouldn’t reveal their membership, and the odds of saving the life of anyone is extremely small, Homer initially couldn’t get into the club.
Fortunately, there are ways to get around the introduction problem, but all of these ways have their own degrees of difficulty. Below are some possible mechanisms to accomplish this:
Any of these methods, or a combination of them, could be used for whitelist population.
Posts in this series: - A Plan for Email over IPv6, part 1 – Introduction, and How Filters Work in IPv6 - A Plan for Email over IPv6, part 2 - Why we use IP blocklists in IPv4 and why we can't in IPv6 - A Plan for Email over IPv6, part 3 - A solution - A Plan for Email over IPv6, part 4 - Population of the whitelists - A Plan for Email over IPv6, part 5 – Removals, key differences and standards