prohibit blind copying on server

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marceloleaes
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prohibit blind copying on server

Post by marceloleaes » 2020-03-03 23:37

Is there a way to disable or prohibit blind copying for all users on the server?

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jimimaseye
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Re: prohibit blind copying on server

Post by jimimaseye » 2020-03-03 23:43

No.

Servers don't know or recognise bcc - Thats a client thing. It's the client that parses the bcc in to recipients and passes to the server for delivery.

[Entered by mobile. Excuse my spelling.]
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SpamassassinForWindows 3.4.0 spamd service
AV: Clamwin + Clamd service + sanesecurity defs : https://www.hmailserver.com/forum/viewtopic.php?f=21&t=26829

marceloleaes
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Re: prohibit blind copying on server

Post by marceloleaes » 2020-03-03 23:59

perhaps a script that at least returns the email sent to the sender. it would not be possible?

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jimimaseye
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Re: prohibit blind copying on server

Post by jimimaseye » 2020-03-04 00:04

marceloleaes wrote:
2020-03-03 23:59
perhaps a script that at least returns the email sent to the sender. it would not be possible?
How is the server script to know what recipient is a bcc?
jimimaseye wrote:
2020-03-03 23:43
Servers don't know or recognise bcc - Thats a client thing. It's the client that parses the bcc in to recipients and passes to the server for delivery.
[Entered by mobile. Excuse my spelling.]
5.7 on test.
SpamassassinForWindows 3.4.0 spamd service
AV: Clamwin + Clamd service + sanesecurity defs : https://www.hmailserver.com/forum/viewtopic.php?f=21&t=26829

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SorenR
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Re: prohibit blind copying on server

Post by SorenR » 2020-03-04 04:12

BCC is simple...

The object oMessage.Recipients(i).Address (i = 0 to oMessage.Recipients.Count-1) contains the list of recipient(s) this particular email is addressed to, it can be 1 or multiple recipients. "Envelope" Recipients can be found as "RCPT TO:" in the SMTP log.

IF the list of recpient(s) do NOT correspond with oMessage.To or oMessage.Cc then the email is either sent to an Alias/Catch-all, as BCC, Spoofed or SPAM. Take your pick :mrgreen:

In case of an alias or catch-all then hMailServer translates the contents of oMessage.Recipients(i).Address to the alias or catch-all address and leaves the original recipient in oMessage.Recipients(i).OriginalAddress.

The thing about BCC is allthough the SENDER saves a copy of the email WITH the BCC address it is not processed as such by the server.
A BCC address email is simply addressed to the person BUT the person is NOT included in oMessage.To and oMessage.Cc.

To understand this fully one needs to understand that an email is like a real life letter in an envelope. There is an address on the envelope and there is an address on the letter itselv and they are NOT required to match.

Envelope To: oMessage.Recipients(i).Address (RCPT TO: in SMTP.log)
Envelope From: oMessage.FromAddress (MAIL FROM: in SMTP.log)

Letter To: oMessage.To
Letter Cc: oMessage.Cc
Letter From: oMessage.From
SørenR.

“Those who don't know history are doomed to repeat it.”
― Edmund Burke

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