why is it (seemingly) so difficult to just return-to-sender spam email?
January 29, 2017 10:01 AM   Subscribe

Email tech geeks: Why is it *not* a common practice to let users reject spam email and return-to-sender - instead of just filtering it to one's trash bin? Because it seems 99% of the time I use an email client, 'block spam' isn't really blocking.

Is it because often by the time an email reaches your inbox, there's no easy way to truly send it back on the path it took to reach you? (Which presumably would likely affect the proxy folks in-between than whoever did the spamming). Even highly rated paid email providers I've looked at do not typically provide this as a regular every-user-can-do-it service. (And by provider, I mean, let's say you were just a everyday user who wanted to use something like Gmail - but it could be any scenario like that where you are just one person and using some big company's product - not an admin providing an email service to your big business).


Thanks mefiters. : )
posted by bitterkitten to Computers & Internet (13 answers total)
What would return to sender accomplish? They'd just ignore it. The real scammy spam doesn't have even supply a real address anyway.
posted by TheAdamist at 10:08 AM on January 29, 2017 [10 favorites]

On Gmail (and many other email providers), Mark As Spam helps train the spam algorithms by telling the system that "this email you thought wasn't spam is actually spam", so that in future similar spam goes straight to the Spam folder instead of the inbox.
posted by EndsOfInvention at 10:10 AM on January 29, 2017 [2 favorites]

I'm with TheAdamist; return-to-sender only affects human emailers and robots that play by the rules.

And the "return to sender" messages as you call them are really just fake error messages, and it's bad practice create systems that fake error messages for your convenience.

If there was a proper "return to sender" message that was human friendly (instead of the text-barf one currently gets with the "your email could not be delivered" messages), it'd be good, but there isn't one built into the email standards, that I know of.
posted by Sunburnt at 10:11 AM on January 29, 2017 [2 favorites]

The senders of spam emails go to extraordinary efforts to mask the origin of their spam. They send it using networks of compromised hardware belonging to oblivious people who didn't keep their computers/routers/internet-fridges patched. Spammers don't hang their own personal email addresses on the spam that they send.

If everyone did find a way to send these emails back, that would double the amount of internet traffic that's composed of spam, while not bothering the spammers one little bit, since the spammers would easily be able to filter their _own_ spams out of their email.

Auto-deleting spam on sight would make more sense, but that would leave you unable to detect when messages you care about are mistakenly going in the spam bin.
posted by emilyw at 10:15 AM on January 29, 2017 [17 favorites]

Don't let the spammers win. If you send something back, you are obviously a real account with real eyes on the email and more spam will be directed your way.
posted by janey47 at 11:53 AM on January 29, 2017 [10 favorites]

What emilyw said. The sender address is trivial to forge.
posted by zrail at 12:35 PM on January 29, 2017

The technical term for this is backscatter.
posted by NormieP at 12:54 PM on January 29, 2017

Return-to-sender just means your server is now also sending spams.
posted by aubilenon at 5:49 PM on January 29, 2017 [1 favorite]

There is a difference between fraud spam and "legitimate" commercial spam. For me personally, legitimate spam is a bigger hassle--the really blatant fraud stuff gets caught by my filter. Commercial spam has an unsubscribe link required by law, that is supposed to do roughly what the return-to-sender does. In terms of cutting down total volume it's about as effective as writing "return to sender" on piece of physical junk mail.
posted by mark k at 8:15 PM on January 29, 2017 [1 favorite]

The protocol that underlies email (Simple Mail Transport Protocol, or SMTP) doesn't really have a "return to sender" function in the way you want one to exist. Once a message has been received, if you then want to return it, you're sending a new email, potentially to a forged return address, and that's what's called backscatter.

SMTP does allow a server to reject email instead of receiving it, though. Backscatter from spam is cut down a bit if the message can be rejected during the initial transfer, but real time rejection is hard, and rejecting legitimate mail is bad, so email administrators are always fighting a battle between blocking spam and allowing legitimate mail through without delay.

Note: none of that answer addresses the problem of mail relays (where there's an intermediate server between the one where the message originates and the one where it's delivered to your inbox); open relays can be used by spammers to drop off mail without having to deal with rejection themselves, so it's generally considered bad to allow an mail server to relay mail except for authorized users. Open relays also contribute to the backscatter problem, but that's not the question you asked.
posted by fedward at 8:54 AM on January 30, 2017

A lot of spam has a forged "from" address (as noted above) but even worse, many times that is the real email address of some poor sap who had nothing to do with creating the spam in the first place.

So if you send something back to that person you've just annoyed and bewildered another completely innocent bystander to the situation, without accomplishing anything useful at all.

Personally I'm in favor of printing out all spam messages & returning them to the sender in the form of a giant dump truck full of returned messages right on top of their head. But to do this, first you have to locate the actual sender, and that ain't easy . . ..
posted by flug at 9:16 AM on January 30, 2017

You might consider using MailWasher Pro from a company named Firetrust. (Sorry, no link.) MailWasher enables you to "look" into your mail server to identify email as spam and to delete or bounce it (literally) before it even gets to your Inbox. Over time, MailWasher accumulates a library of spam addresses so that it recognizes those messages and sets them to be automatically bounced. You can add your own customized rules so that, for example, emails to multiple recipients are marked for your special attention (and permanently blocking the Sender if you wish).

Very good product. Lifetime license is available.
posted by John Borrowman at 12:51 PM on January 30, 2017

Ha ha, ask this question, then look through my Exchange/Sendmail logs for NDRs . A veritable rogue's den of malfeasance, it appears! Rife with Spammers, you'd say! How dare I allow this to go on would be your response! But who they say they're from is fake, just as if I mailed you a piece of poop in the shape of Trumpo's head and put my neighbor's address on the return. What good would putting a larger piece of poop that looked even more like Trumpo in the mail to my neighbor? You're just trumpooping (pooptrumping?) an innocent person.

Additionally, even if they weren't faking the reply-to, you'd avoid it for the same reason you don't want to engage with any criminal/thug/malicious prankster: "Hi, nameless entity of unknown origin. Please allow me to confirm the existence of a living, breathing, not-too-email-savvy yet emotional human that reads your mails and isn't happy about it! In the name of all that's good and decent, please consider my feelings and stop sending unsolicited emails."
posted by dozo at 1:09 PM on January 30, 2017

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