Is "bouncing" spam a good idea?

[Binky]

I've been using CIECHECK very happily for years as an email checker. It does a good job of automatically deleting spams off the server based on a blacklist of email addresses, domains, or keywords in the Subject. But I worry that good email might get bounced if from a banned domain. I'd at least like the sender to know it was bounced so they could somehow try again or, at least, not think I was just ignoring their mail. So I'm thinking of switching to MAILWASHER, which sends a bounce message back to the sender.

Two questions:
1. Do bounces help get you off spammer lists, help you stay on them, or make no difference?

2. In MAILWASHER can I edit the bounce message so that valid senders will know what's going on?

[sheila]

Based on my long-time experience in the spamcop newsgroups, and other email related fora, I would say:

Do bounces help get you off spammer lists, help you stay on them, or make no difference?

No difference. Also, in my personal experience bouncing spam back from my kids accounts, no difference. The spammers seem to take no note of the bounces.

I have no experience with Mail Washer, so I'll leave that for someone else to field.

Some people say that bouncing spam is a very bad idea, because the spammers sometimes put real email addresses in the SMTP envelope Sender, real email addresses that belong to some innocent third party. And then they get all the bounce messages. Which does no good and probably just overloads their mail server.

So unless you have a really good reason to bounce the messages, you should not do so.

Believing that legitimate messages will go lost without a bounce notification may be a good enough reason.

[Rich]

Some people say that bouncing spam is a very bad idea, because the spammers sometimes put real email addresses in the SMTP envelope Sender, real email addresses that belong to some innocent third party.

I find that about 10% of my unwanted email falls into this category. Receivers who blindly assume that the From: field identifies who the spam is actually from.

It should also be noted that if you bounce spam by using the From: field, you should also expect to get lots of autoresponder messages including away notifications, newsgroups, and newsletters.

[sheila]

It should also be noted that if you bounce spam by using the From: field, you should also expect to get lots of autoresponder messages including away notifications, newsgroups, and newsletters.
Actually, no. A true bounce message has an empty SMTP envelope sender, and therefore gets no responses of any kind. That said, I don't know how these "bounce" messages sent by Mail Washer work, and so I suppose that may be possible with that software. If so, I would not use that "bounce" feature.

[Rich]

Actually, no. A true bounce message has an empty SMTP envelope sender, and therefore gets no responses of any kind.
Yes, good point.

However, I have seen many applications/systems that instead of sending a true bounce actually just send a reply.

[sheila]

Ah, Rich, upon re-reading a little more closely, I also notice that you said, "bouncing using the From field", which of course is not the correct way to bounce an email either.

I would be highly suspect of any software that POPs the mail from your email account and then claims to send a "bounce" message. Double check that it is sending the bounce messages to the SMTP envelope sender (which is the correct method) and not to the address in the from-field.

You can determine the SMTP envelope sender on messages delivered to a Qmail system (such as the mail system at FutureQuest) by inspecting the headers for the Return-path: header. The email address in that field is the SMTP envelope sender. It is often the same as the address in the From field, but not necessarily.

A True bounce message will have the following header, among others, when delivered to a Qmail system:

Return-path: <>

which signifies an empty SMTP envelope sender.

For those using POP clients that claim to bounce messages, send yourself a bounce message, and verify that the Return-path is empty. Also, you should try to determine whether the application uses the email address in the From field, or whether it uses the SMTP envelope sender. If it doesn't comply with these two conditions, I would recommend not using the bounce feature offered by that software.

[TheEgo]

I can confirm that MailWasher sets the Return-path header correctly on the bounce message, and that it sends to the SMTP envelope address.

But on the larger question -- Does it actually help? -- the jury is still out. I've been using it for three months now, but just when it seems like the stuff is finally dropping off, I get 15 people trying to sell me a mortgage. :fire:
In MAILWASHER can I edit the bounce message so that valid senders will know what's going on? No, you can't edit the bounce message. That's why I don't let it do its own thing without supervision.

That being said, I find that it does an excellent job of identifying honest-to-God spam. And only once has it wanted to bounce a "friendly" -- somehow Dotster got itself blacklisted, so I added it to my Friends list. Other commercial (non-spam) email only gets a "Possible Spam" rating at worst, which won't be bounced by default. I haven't seen any personal mail get the evil eye so far.

The Ego