Why does email bounce?

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Dear Leo,

If I am correct, you are the only person who has elaborately explained in simple English giving out different reasons for bouncing of e-mail.

Well Done. A very good article. I enjoyed reading it.

Thanks for making a layman like me to understand the technical things so simply.

God Bless you.

Regards.

Sankara Narayanan

Here's a message I got, after I reconfigured my reverse DNS or PTR record. Some senders, some of the time got this message when they tried to email us. Not all external email was bounced, which suggests something spam-blockish about this error.
What I don't understand is that the bouncing happened AFTER we made the change to our PTR record. Do you think it's the aftereffects of reconfiguring a PTR record, and if so, can you explain why this would happen after the change was pushed out (but not before it was fully propagated)? Thanks so much, Susan

Hi. This is the qmail-send program at hostXXX.ipowerweb.com.
I'm afraid I wasn't able to deliver your message to the following addresses.
This is a permanent error; I've given up. Sorry it didn't work out.

:
vdeliver: Invalid or unknown virtual user 'xxxx'

some time i get this error message after sending a message like...

553 sorry, Authentication failed or timed out. Please do get messages first to authenticate yourself.(#4.4.3)

please Help....

Hi,
I'm also getting the following error in the bounced mail text. Can anyone please tell me what is happening, and how this can be fixed ? Thanks in advance.

Hi. This is the qmail-send program at rediffmail.com.
I'm afraid I wasn't able to deliver your message to the following
addresses.
This is a permanent error; I've given up. Sorry it didn't work out.

:
This message is looping: it already has my Delivered-To line. (#5.4.6)

dear leo,

I have a complete different issue.

I am trying to send a mail using mapi application &outlook express.

When I am attempting to receive mail adresses from database or ini file It's gives me the #5.1.1 error ie. I am afraiding etc. as mentioned in ur article.

I am able to send mails properly through hardcore programming bUT i dont want to do that.

Plz, help me.

REgards,

kamlesh

Hi

Great article. Helped me a lot.

For one domain on our server we are getting a lot of

"unrouteable mail domain"

when the site owner sends out a bulk email so she thinks it is our problem. But I am not too sure.

Any ideas?

thanks

Hi. This is the qmail-send program at yahoo.com.
I'm afraid I wasn't able to deliver your message to the following
addresses.
This is a permanent error; I've given up. Sorry it didn't work out.

:
209.191.89.172 does not like recipient.
Remote host said: 550 relaying denied for
Giving up on 209.191.89.172.

Hi, this was a very helpful artical...however I have a dillemma. I use a domain name which I purchased. This domain name forwards all my emails to whichever email address I specify. This way, I do not have to alert everyone in the world when I switch ISP's and can no longer retrieve mail. I simply use email@mydomain.com and viola! i have an email address forever.

Well, this has worked great up until about 5 months ago. I am now getting all sorts of these "unable to relay" errors. Why can't I just get them to leave me alone! I am not a spammer! Why can't I just use the internet the way it was designed to be used, and get the isp's to just BUTT OUT!!!

Hi Leo,

I have a client who used to have an email address from her web site that forwarded to her ISP. She has since switched her hosting to my company AND her ISP to a new provider.

I have setup her web hosting account as I would any other new account and changed her DNS settings to the DNS of the new host. I also setup forwarding for her email that comes into the Web hosting account to her new ISP (which is the same as the old Web hosting site - she wanted to keep info@ as the email username).

Most of the time things work fine, but ocassionally, she sends me an "unknown user" error message she has received from her friends or clients because the new Web hosting email address forwards the incoming email to the old ISP email address (which bounces correctly) instead of forwarding it to the new ISP email address.

I am frustrated because I don't understand how the new account I set up could ever "know" how to forward to the old ISP address. Is there a registry or something that this forwarding information is on? This has been going on for about 6 months now.

Thanks in advance for any light you can shine on this problem.

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It *sounds* like stale DNS entry somewhere.

Did you set up an MX (mail exchange) record for her domain to point to your
mail server where the forwarding happens? If not you might consider adding one.
If there's no MX record mailer mailers are supposed to use the IP of the
destination domain as the target server, but I've always been more comfortable
adding an explicit MX to say "the mailer for this domain is here".

Six months is a long time for a DNS entry to be stale. You might also consider
"refreshing" DNS by making a change that would force your DNS records to get
re-propagated.

Good luck!

Leo
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