I can send a message to my address in 2020 using a 2003 Fedora Core 1 box without a domain using only what's part of the POSIX standard, and I'll receive it just fine.
I just did a few days ago, actually. It even got past my provider's spam filter.
I could probably have done it using earlier software than 2003-era mail/mailx, but that was the quickest way I could find to send an attachment given the software on hand.
However, I, as a receiver of email, get thousands of spam messages a day. So, I use services that block them before they even reach my view, or get sent directly to the spam folder.
If you want to send me an email, that's solved. If you want to send it to ten thousand people on your mailing list, and not have it end up in the spam folder, you may have more work.
There was a big fit thrown on this website a year or two ago when one transactional mail provider (MailChimp?) said they were banning crypto companies with ICOs from their service. They literally put "ICOs are not welcome" in their Terms of Service. Why? Because first off, ICOs are scams. And that means they buy email lists, and then spam the shit out of people with "buy into our ICO!" emails, which get immediately shitcanned into the spam folder by 99.99% of users -- they're no different than Nigerian Princes, as far as most people care. That behavior tanks the reputation of the sender, and you cannot reason with The Algorithm once it "recognizes" you as spam. That kind of problem is not a minor inconvenience to companies like Mailgun, it's an existential threat.
You might miss something valuable. Perhaps from a long-lost relative. Or a prospective client or employer.
And once you're actually looking through the spam folder, what good is it really?
tl;dr: Abuse ruins it for everyone.
I work on the filtering side of the world so I see a lot of the challenges that even purportedly good actors face. Each provider does better or worse at controlling abuse. These things all have a cost:
* IPs -- You need to send from a variety of IPs. They have warmup time before they can be safely used. One bad guy can burn that IP and everyone who shares. Most ESPs aren't going to have dedicated IPs for each (or those are for high tiers).
* Dmarc/dkim/spf -- Passing validation can be hard since it requires your client to work with you.
* Abuse reports -- Likely huge volume
* Bounces -- They can count against the customer. How much is OK (e.g. AWS SES will cut you off if your bounce rate gets too high)?
* Throwaway account abuse -- Huge issue, this threshold is a simple hammer (so now bad guys need ~10x more throwaway accounts).
* Account takeover -- That good guy is now sending out crap. Now what?
* Post-abuse cleanup -- Good luck going around and working with major providers to get yourself unblocked. Its a huge time sink.
By using Mailgun, etc all of the above becomes their problem. On top of it they'll offer analytics, help crafting content that works in varying mail clients, etc.
A small business type sender doesn't need much of this (other than maybe the technical help). But at some point, the scales tip.
I'm curious, is that specific to IPv4 or you see the same phenomenon with IPv6 where providers allocate /64 or /48 to customers? Or there simply isn't enough sending volume from IPv6 at the moment to warrant specific filtering?
Blocking via IP on V6 is tricky since it’s not clear what a safe/useful block range would be.
They specified that it wasn't even if you could ignore the spam issue. I said that it was if you ignored the spam issue. The first post in this thread was "We've made sending electronic mail way too complicated under the guise of fighting spam."
I'm aware that it won't get past every spam filter, but it gets past both Gmail's and my own provider (a smaller, non-American one), which is good enough for my own use. My claim was that sending electronic mail is a solved problem, because it is.
Communication is much more than just broadcasting, just as email is about more than sending emails.
Agreed. I mean, I can _probably_ remember enough to be able to send mail using just telnet without even needing to look anything up. (And that mail, without any mime parts or urls - it very very likely to not fall into any of the spam filtering on my inbound email accounts...)
