If the TLS is terminated on the device and all it's using AWS for is a static ip and inbound port for email, that seems pretty harmless.

Seems like a stupid design decision at that point to have a dedicated instance per user. For a pass-through they could multiplex tens of thousands of customers easily onto a single instance.

No, SMTP runs on port 25 only. You need an IP per end mailserver if you are not terminating TLS on the multiplexer.

It's not stupid.

One computer can have multiple ip addresses though. I don't know if it works on AWS or for email but I think it's at least theoretically possible.

Please read up on how email works before arriving at this conclusion.

Would they still keep their own separate static IPs then?

You can assign multiple interfaces to an EC2 instance and each of those can have a static IP. I think there is a hard cap on the amount of interfaces you can assign to a single machine, so you'd still have to scale out horizontally at some point.

That's exactly how it works

I feel that the internet is doing the full circle again, mediated by rent seekers -

1. all IPs are the same, email for everyone

2. residential IPs cannot into email cause spam

3. consumers don't get into IPs anymore cause CGNAT

3. AWS collects all the other available IPs and rents them out

4. consumers can now get IPs again, rented from AWS

5. ...

6. profit !

Spot on.

Elsewhere in the thread gsreenivas mentions that the solution is too expensive for spammers and so they haven't had a problem with that yet, so we've actually moved to the original solution to spam: charge for sending e-mail*. The original proposal was to charge per email but an annual subscription would have the same effect in the right market (for now.)

* Wasn't it Bill Gates who suggested that?

But isn't this charging also for receiving?

> residential IPs cannot into email cause spam

Strictly, that's dynamic IPs. The Venn diagram may almost be circular, but not quite. Part of the point being that it's much easier to block static IPs, while a spammer on a dynamic IP will evade any blocks when their IP address changes.

My in-laws outbound email broke recently because, being on a dynamic IP, they'd been set up to send through their ISP's smarthost. Then they changed ISP :P.

This is even missing a trick: unless its politically indicated, AWS does not ban its customers for spamming, high-rate crawling or other abuses, causing its IP ranges to be widely blocked.

So now Amazon gets to market segment and sells a trusted email service, too!