cancel
Showing results for 
Search instead for 
Did you mean: 

Email to invalid mailbox disappearing without rejection msg

N/A

Email to invalid mailbox disappearing without rejection msg

Hi,

I've just switched off the catchall option for my email and sent a few test messages to some (now) invalid mailboxes. I had expected to get rejection messages but instead I'm getting nothing - the emails just seem to disappear into a black hole.

If someone emails me and accidentally gets the address wrong, then surely they should get a rejection message? Doesn't this also have a bearing on spammers who sometimes send emails to random mailboxes, and if they don't get a rejection then start to bombard the mailbox with spam?
16 REPLIES
waldron
Grafter
Posts: 348
Registered: 28-07-2007

Email to invalid mailbox disappearing without rejection msg

I raised this subject earlier in a thread "Catchall switched off", as an email sent to me with my 'myname' spelt wrongly had disappeared.
I've done similar tests and none have received a rejection message. Although if the 'username' is spelt wrongly it is rejected 'Host unknown'
N/A

Email to invalid mailbox disappearing without rejection msg

Hmm, I'm sure (I hope!) it's not meant to work like this. Anyone from Plusnet able to comment...?
spinecho
Grafter
Posts: 26
Registered: 26-07-2007

Email to invalid mailbox disappearing without rejection msg

I noted same probem in the mailbox thread I started.

I took the option to switch off username@username.plus.com e-mail in the e-mail settings.

I have sent multiple test e-mails to this and none have bounced and none arived by my 4th test today. 1st to third tests some were still getting through but looks like it took over nights for system to fully update.

Very concerning that none are bouncing.

Francis.
N/A

Email to invalid mailbox disappearing without rejection msg

I'm getting something similar - have had a call raised for a few days to try and get to the bottom of it, but no joy as yet:

I set up my new freebie domain;
Changed my plus.com default mailbox;
Enabled the catchall to the new plus.com default mailbox name.

Now:
anything@newdomain gets through OK;
postmaster@plus.com domain gets through OK;
anything@plus.com domain disappears into the ether with no rejection to the sending account...

Really weird...
Plusnet Staff
Plusnet Staff
Posts: 12,169
Thanks: 18
Fixes: 1
Registered: 04-04-2007

Re: Email to invalid mailbox disappearing without rejection

Quote
I've just switched off the catchall option for my email and sent a few test messages to some (now) invalid mailboxes. I had expected to get rejection messages but instead I'm getting nothing - the emails just seem to disappear into a black hole.


This is the way it was designed, by switching off the catch-all you're effectively blackholing those addresses. So rather than deliver the mails or bounce them they are silently binned.

Quote
If someone emails me and accidentally gets the address wrong, then surely they should get a rejection message? Doesn't this also have a bearing on spammers who sometimes send emails to random mailboxes, and if they don't get a rejection then start to bombard the mailbox with spam?


As I say there's no bounce with the way it's set up because it's designed as a blackhole and whilst I suppose that a spammer could target a blackholed address other than resource on the mxcore/mxlast servers to identify and delete them it shouldn't make much difference. The mails aren't stored so there's no storage issue and they are binned before they get to the spam scanning which is the most resource hungry part of the process.
Plusnet Staff
Plusnet Staff
Posts: 12,169
Thanks: 18
Fixes: 1
Registered: 04-04-2007

Email to invalid mailbox disappearing without rejection msg

Quote
I'm getting something similar - have had a call raised for a few days to try and get to the bottom of it, but no joy as yet:


Hmm, this is odd, I've tried something but I'm not sure if it will fix it and sent a couple of test mails, one to postmaster@username and the other to one of the named addresses on your tickets. I'll have a check in a few minutes to see if it's worked.
Plusnet Staff
Plusnet Staff
Posts: 12,169
Thanks: 18
Fixes: 1
Registered: 04-04-2007

Email to invalid mailbox disappearing without rejection msg

Seems to be the same so I've sent it to the network guys to investigate.
N/A

Re: Email to invalid mailbox disappearing without rejection

Quote
As I say there's no bounce with the way it's set up because it's designed as a blackhole and whilst I suppose that a spammer could target a blackholed address other than resource on the mxcore/mxlast servers to identify and delete them it shouldn't make much difference. The mails aren't stored so there's no storage issue and they are binned before they get to the spam scanning which is the most resource hungry part of the process.


So if a sender mis-addresses an email to me by getting the user part of the email address wrong (maybe they guessed first.last@mydomain instead of last@mydomain for example), then the email is lost and there's no Delivery Status Notification, but the sender thinks it's got through OK?
Community Veteran
Posts: 14,469
Registered: 30-07-2007

Email to invalid mailbox disappearing without rejection msg

By switching off the catch-all you effectively remove the capability of catching mis-spelt email addresses. That is one of the draw-backs of doing this. You have to decide is it worth being able to catch mis-spelt emails at the expense of spam or you ditch the spam and only get correctly addressed email.

You can't have both!
N/A

Email to invalid mailbox disappearing without rejection msg

Quote
By switching off the catch-all you effectively remove the capability of catching mis-spelt email addresses. That is one of the draw-backs of doing this. You have to decide is it worth being able to catch mis-spelt emails at the expense of spam or you ditch the spam and only get correctly addressed email.

You can't have both!


Well that's a shame, avoiding one problem only to have another. I'm not sure which is worse! Is it really that difficult to reject incoming SMTP connections that specify non-existent mailboxes?

In the meantime I'll probably move my free domain's email hosting to somewhere else.
N/A

Email to invalid mailbox disappearing without rejection msg

Thanks Dave... fingers crossed.
Mand
Grafter
Posts: 5,560
Thanks: 1
Registered: 05-04-2007

Email to invalid mailbox disappearing without rejection msg

Quote

Well that's a shame, avoiding one problem only to have another. I'm not sure which is worse! Is it really that difficult to reject incoming SMTP connections that specify non-existent mailboxes?


Hi there,

We send bounces for domains which are invalid, but not for mailboxes.

It's not difficult to issue a bounce, but it would be clear to a spammer which mailboxes were checked and which were not, increasing the chances of you receiving more spam to the mailboxes you actually use. In addition to this, if the sender address is spoofed (as with most spam) all this will achieve is sending some poor soul thousands of bounce messages.
N/A

Email to invalid mailbox disappearing without rejection msg

Quote
Well that's a shame, avoiding one problem only to have another. I'm not sure which is worse! Is it really that difficult to reject incoming SMTP connections that specify non-existent mailboxes?

Indeed it is a shame (well, that's putting it politely).
- If I enable catchall, nothing bounces, as it goes to catchall
- If I disable catchall, it gets binned without bouncing

I think the earlier statement that this is how it is supposed to work ought to be reconsidered.
MrToast
Grafter
Posts: 550
Registered: 31-07-2007

Email to invalid mailbox disappearing without rejection msg

Now I'm confused.

There are two relevant settings on the account. Blackhole and Catchall.

Before Catchall was available I had my default blackholed and mail to non existant mailboxes resulted in a 550 error.

The advice here is at odds with that which I received to my ticket ID: 22046423 which is that no 550 errors are currently being generated due to problem ID43448 which is under investigation.

Mail sent via SMTP should generate an error if it can't be delivered to a mailbox:

Both RFC 821 and 2821 state:

>>If the recipient is known not to be a deliverable address, the SMTP server returns a 550 reply, typically with a string such as "no such user - " and the mailbox name <<