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Author Topic: Curious problem with particular email not sending  (Read 1887 times)

sheddyian

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Curious problem with particular email not sending
« on: June 10, 2015, 11:16:41 AM »

First, I've got around this problem, so I'm not desperate for an answer, but I thought I'd share it as it's a bit weird.  I'd be interested in anyone's thoughts though.

I use Windows 7, with Windows Live Mail with a Gmail account (using IMAP).  I've got Panda free antivirus installed.

Yesterday, I was asked if there's a way to tell if a PC has been switched on while you weren't there.  There is - a nifty little utility from Nirsoft.  (I recommend a peruse around the site, there's loads of handy things there - eg I use wakemeonlan quite a bit, not so much for waking remote computers, but for scanning the lan and easily finding the ip address allocated to a particular device) http://www.nirsoft.net/

The program in question here has a mildly unfortunate name - TurnedOnTimesView.

I wrote a quick email, and attached the zip file I'd downloaded from the Nirsoft site, and sent it.  No errors appeared.

Later, I was told that the email hadn't arrived.

I checked in my outbox and sent items - the email wasn't there!  I was sure I'd sent it.  So I sent it again.  And looked in my sent items.  And it wasn't there!  I sent another plain email, that correctly appeared in sent items once it had sent.

The file passes a virus scan with no problems.  But, in any case, the antivirus didn't tell me it had blocked it.  And there's no sign of it doing so when I view the Panda antivirus log.

The zip file is 67K, so I don't think I'm exceeding a size.  (In any case, read on - I did a few tests..)

I unzipped the file, and recompressed it using 7zip, and set a simple password for it (also on the filenames).  The 7zip file was called TOT.7z
I emailed this, and it appeaers to have worked - it showed up in my sent items.

Wanting to prove that it was the naming that was causing problems (perhaps a spam filter somewhere?) I then created a plain text file called "test document.txt" with "this is a test" in it.  I then made four zip/7z files of this, with differing names.  None of these zip/7z files were password protected.

Here's the baffling results :

test document.zip              sent ok
turnedontimesview.zip        sent ok
test document.7z                sent ok
turnedontimesview.7z         disappeared  [edit : has just appeared in sent items 30 minutes late!]

OK, so now that last test has appeared it means this test hasn't proved much.  More tests to be done I think.  The two attempts at sending the original zip file still haven't appeared in the "sent items" list.

Ian


« Last Edit: June 10, 2015, 11:24:38 AM by sheddyian »
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Dray

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Re: Curious problem with particular email not sending
« Reply #1 on: June 10, 2015, 12:49:02 PM »

Try checking the mail headers of the email http://mxtoolbox.com/EmailHeaders.aspx
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sheddyian

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Re: Curious problem with particular email not sending
« Reply #2 on: June 10, 2015, 12:57:53 PM »

Try checking the mail headers of the email http://mxtoolbox.com/EmailHeaders.aspx

I don't think I can - the email just disappears after I press send.  Doesn't get delivered, doesn't bounce, doesn't go into spam, or sent items, or outbox, or pending or anything.  Just disappears.

A few more tests just now seem to show that something (Google or Live Mail program) is filtering out zip/7z files with .exe in them.  Which is perhaps quite understandable, but you'd think it would bounce or you'd get an error or warning. 

If that's the case, the workaround is what I used anyway - to password protect the zip, and to choose to encrypt the filenames as well.  That file was sent successfully and appeared in my outbox as expected.

Ian
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Dray

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Re: Curious problem with particular email not sending
« Reply #3 on: June 10, 2015, 01:09:04 PM »

Sorry, yes you can only check headers on received emails.

Maybe this? http://www.askvg.com/how-to-stop-windows-live-mail-from-blocking-unsupported-file-types-in-attachments/
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d2d4j

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Re: Curious problem with particular email not sending
« Reply #4 on: June 10, 2015, 03:10:25 PM »

Hi

Mail servers will decrypt zip files and look for hash signatures. If matched, what happens next depends upon how the mail admin is setup, so may be sent to spam, maybe deleted or may be stopped etc.

A big no no is emailing executable files, usually in any form ie renaming exe to any extension as hash filtering should detect it is still an executable file.

Therefore, this will be the reason of non delivery but it depends upon the mail server setup.

No emails are read by humans normally

Many thanks

John
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