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If you send email to an invalid address or a closed account, usually you'll get a bounce back. Usually. The problem is that you cannot count on bounces.

Will my Outlook Express email that I send bounce back to me to let me know if the recipient's email address is closed or no longer exists or will it just go out into space never to be seen again?

Unfortunately, the answer is:

a) both

b) neither

and of course

c) all of the above.

Email bounce messages are both annoying and informative. They can help you fix a problem with an email you've sent, or they can simply be another message in a big pile of spam.

Unfortunately about the only thing you can count on is that you cannot count on bounce messages.

First, I have to ask, what does it mean for an account to be "closed"? It could mean:

  • The user stopped using it. Email will still be successfully received, and simply accumulate. Nothing that would cause a bounce.

  • The user could have "closed" the account, but the ISP hasn't released or actually deleted it yet. This is probably more common than you think, particularly with free email accounts. While the user thinks that things are closed and deleted, in reality all the ISP may have done is restricted his access until they get around to cleaning up "dead" accounts. Email may still be successfully received and accumulate until the cleanup happens.

  • The account is actually closed. Here's where things get interesting.

With the ever-increasing influx of spam, many ISPs are choosing to ignore mail destined for invalid destinations. Why? To avoid flooding the internet with even more noise.

You've probably received bounce messages for email you didn't send. Spammers have "spoofed" the email such that it looks like it's coming from you and then blasted it out to anything they can find that looks like an email address. Some ISPs generate bounces if those addresses are invalid, and that's what you're seeing. Other ISPs don't generate bounces, since they're as bogus as the spam that caused them.

"If you send an email to someone, and you don't get a bounce, that tells you nothing."

So, the bottom line here is that an ISP may, or may not, return a bounce on an invalid email address - or on any error, for that matter.

But it gets worse.

Because so many bounce messages are the result of spam, spam filters are now occasionally filtering them out as spam. So even if the recipient's email provider does send a bounce, there's actually no guarantee you'll get it!

Now, I will say this: most of the time bounces are generated and received and work pretty much as you expect. But the problem is that you can't count on it.

If you send an email to someone and don't get a bounce, that tells you nothing. They could have received the email, or not. There's actually no way to tell.

Article C2870 - December 13, 2006 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

December 15, 2006 8:19 PM

I personally like when it bounces back. Just today at work, an email I sent to my boss and two of our vendors got bounced back. Looking at the reason given, I quickly saw that I had spelled the address wrong by 1 letter. Was able to resend it with the correct I don't have the 300lb purple gorrilla called a boss banging on my desk. hahahaha. Thanks Leo for the tips.

December 22, 2006 5:20 AM

Since the prospect of a bounce is so iffy, it's too bad we cannot offer an incentive similar to how the US Postal Service does it. My idea would be to join a service and receive an account number. Then, if I wanted to ensure notification of a mis-addressed eMail, then I'd simply flag the eMail with my account number. If it's bad, then the ISP, by bouncing it *to the service,* would later be reimbursed for its trouble. This could be done any number of ways with the main goal being to reduce the money-handling costs.

July 8, 2008 6:08 AM

wanted to know what to do with annoying emails

thank you

Sayad Hanayat
March 14, 2009 8:03 AM

I want to my email that i send one hour ago to not be read by the person that i sent hem email. How to able to solve this problem.Thanks.

You cannot. Once email has been sent, it is out of your control.
- Leo

Nancy Miller
October 5, 2010 4:24 PM

If someone requests you to send an email to their address and it bounces, do they have any access to that in order to add a viris?

They could certainly make something that LOOKS like a bounce that also has a virus.

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