Topic: Reject email with BCC:

[byte]

Hi,

Does any of you guys know how you can stop a email which has a email user on the BCC line at the server?

So if an email has a TO: CC: the emails still get in but if an email has BCC: then the email is blocked!

Is this possible?

Thanks for any pointers!

[Brenno]

At first, I thought that you could probably do this with procmail by specifying the "based on" as "custom headers" and then adding the header for bcc: in the "criterion."  Then I did some tests.

By nature, the bcc: does not produce message headers for the recipient (and really, it shouldn't - that's why it's called a Blind Carbon Copy!)

So, I don't know the answer to your question, but I do know now that procmail won't work.

Greater question is why you would wish to do this?

[RayG]

I am doing something like this with SpamAssassin but I'm dropping the mail once it's come in rather than rejecting it outright. I compare the "DileveredTo" header to the "ToCc" header and if there's no match, assume the addressee was in the BCC.

For me, this is a spam control issue.

[Brenno]

For business reasons, I can't be dropping the bcc: recipient from email, nor can I block email that contains a bcc: recipient.

I would rely on SpamAssassin working normally to remove Spam based it's featured criteria.

[guest22]

http://no.longer.valid/mantis/bug_view_page.php?bug_id=89

[wallyrp]

Good Afternoon,

Was looking at this thread with interest. I too would be able to block all external, not internal, email with BCC in any of the headers. It seems that some spam folks use the BCC line to get email through. I use ASSP at the moment on the 6.01 custom ISO and it works great for me in reducing spam. I've looked at spamassassin and may switch to it next year.

[CharlieBrady]

It seems that some spam folks use the BCC line to get email through.

You're mistaken. All spam uses SMTP for transport - the recipients are part of the SMTP transaction and the To: etc headers in the message body (including any Bcc: headers if they appear, which they very seldom will) are ignored.

[hordeusr]

Good Afternoon,

Was looking at this thread with interest. I too would be able to block all external, not internal, email with BCC in any of the headers. It seems that some spam folks use the BCC line to get email through. I use ASSP at the moment on the 6.01 custom ISO and it works great for me in reducing spam. I've looked at spamassassin and may switch to it next year.

I've used ASSP and spamassassin...ASSP is far superior on my work server.  Much less server load, and nearly perfect accuracy.  It won't work well with just a few accounts though.  As far as BCC...that's not the spam problem.  Use ASSP (or spamassassin on smaller installs).

[wallyrp]

Good Evening,

Ok, evidently there is no way to block external email with BCC? Regardless of the spam issue, I still would like to block any email from the outside that has anything in the BCC field.

[dmajwool]

I have setup my email client reply templates always to bcc to myself.

I do this so that I can reply to mail in a single pop3 account from any one of several workstations (home, office, etc) and each location gets a copy of all my replies, threaded in with the third party's mails.

Your proposed rule wouldn't work for any users who use this or similar schemes.

David

[hordeusr]

Our users frequently use BCC when sending to a large number people (that aren't in a group or mailing list).  That way the list of e-mail addresses isn't sent to everyone.  It's good e-mail etiquette IMO.

[CharlieBrady]

Regardless of the spam issue, I still would like to block any email from the outside that has anything in the BCC field.

You won't get any. It's a violation of SMTP to pass on messages without first stripping the bcc field. It's not very b if you send it on, is it?