You can send email from an EC2 instance but good luck getting anyone to accept it. A lot of email providers block EC2 wholesale, or if they do accept it you are going to have to have a long standing reputation.

What do you mean by blocking "wholesale"? I started hosting an email server in EC2 and the worst I've had is my emails going to a spam folder if that person hasn't received an email from my address yet (and never after they've marked me as not being spam). That happened surprisingly rarely and didn't feel like much worse than I would get by just sending people email from gmail with an address they don't know. I don't think things are as bas as you make them out to be.

edit: I guess I should be clear that I have an elastic IP (which is free) and setup reverse DNS and DKIM and SPF, but I think those are fairly standard now a days (I don't know honestly I've only run an email server for a few months).

Deliverability is a moving target, so you can’t really rely on your delivery metrics from last week.

Why? The SPAM Scoring Industry is a kind of monoculture that will impede or cancel delivery of messages. Most big email providers outsource SPAM scoring to a third party like Symantec or Brightworks. And when your email is found offensive by Brightworks with one of their clients, you’re banned on all of their clients. Part of how SPAM scorers gather intel us by hooking into the CFL system so they get a notification when a user hits the junk button to delete an email. Another way is by checking for mass duplication in your emails. Another way is tracking open rates via the email provider’s UI sending metrics to the scorer’s APIs.

And then there’s the CIDR block lists they coordinate and distribute as a courtesy for their customers. So you might be able to deliver to @gmail.com and then @yahoo.com won’t even take a connection from your server’s IP.

Why does all this happen? According to my friend who works for a midrange ISP on their email service, they have about 120PB to store real email. And the amount of SPAM they reject outright (never reaches any box, not even the junk box) is 93% of all their email traffic. They simply can’t afford to store all the SPAM.

It depends on whom you send to. Like ironically I sent an abuse complaint to Verizon for a spammer and got rejected because they blocked all of Digital Ocean's IP space. Yahoo was particularly difficult too sending me a response saying they won't take my mail immediately on a single email to my brother. I had to go through a lot to get that fixed. Again this was due to being on cloud provider IP space.

GMail is more reasonable with perhaps being spam filtered but never blocked outright. I have also been blocked by government labs and academic institutions. I also have complied with RDNS, DKIM, SPF and got a top score on mx toolbox. Now that I have been up for a while I have had less issues besides with the ones that block cloud provider spaces.

Microsoft is the toughest one. Fortunately, I don't have friends that use outlook.com or w/e

Does your email get blocked if it is sent to a business on O365?

haven't tried in a while. It can, they dont' follow all the rules and do a little more blocking in the interest of their users or based off a ML spam detection or something.

Some things that should be delivered are not. I'd have to dig back into this to see what the exact issue is.

unfortunately DO does not seem to be as active as Amazon in maintaining the reputation of their IPs.

This is very consistent with what our experience has been with Elastic IPs combined with email authentication and blacklist monitoring.

> I guess I should be clear that I have an elastic IP (which is free)

Free when in use, you pay for it when it is not in use.

You can send email using EC2 instances, including mass commercial campaigns (aka "legal spam"...).

However, there are a few things to do, more specifically, you must contact AWS to get "clean" IP ranges (fresh IPs, never allocated to instances), sign some agreements and pay additional fees.

It's not exactly as simple as an API call to create an ec2 instance, but it's doable.

With random IPs, there is a good chance indeed that it is already burnt by a previous allocation.

This is not a god situation. So, EC2 are handy and flexible servers, but not really because some arbitrary internet services are banned, and in all of a sudden your whole setup depends on the cloud provider. Talk about tight coupling. We go backwards. This is really sad.

> I thought that sending email from EC2 instance was not allowed and only option was using their SES service.

Amazon EC2 throttles traffic on port 25 of all EC2 instances by default, but you can request that this throttle be removed: https://aws.amazon.com/premiumsupport/knowledge-center/ec2-p...

Doubt that AWS would allow anyone to send on behalf of 3 parties like Helm appears to do though.

I'm pretty sure it's allowed, it's just that you'll get caught in every spam filter. I don't know if they've considered that problem, or they're just hoping that using the same IPs long-term will fix the problem in reputation-based blacklists.

I guess email can be sent from the residential connection but recieved through EC2?

You can request email sending support when you set up reverse DNS.