Move addresses from To to Bcc?
Jethro R Binks
jethro.binks at strath.ac.uk
Thu Apr 22 09:14:07 IST 2010
On Thu, 22 Apr 2010, Pete Russell wrote:
> Its possible this is an MTA question and not an MS question?
I'd say it's an MTA issue really.
> Every day we see staff send email to customers and students in massive
> lists. Everyone the message is addressed to is listed in the To: field.
> Would it make sense to have a test for more than x entries in the To:
> field so move all of the addresses to Bcc: ?
> If this did make sense would it be very difficult?
Here's what I say to my users when overuse of To:/Cc: occurs:
It is poor practice to send a message to a large number of recipients
listed in the To: or Cc: field, as you have done with a recent message.
As well as damaging privacy by exposing everyone's email address to
everyone else, it is difficult to read, and can cause problems with some
mail clients, for example, they fail to complete downloading the message
and keep trying to do so over and over again.
If you wish to send out a message to a large number of people, then a
better way to do so would be to address the message to yourself or some
other primary recipient in the To: header, and place all the other
recipients in the Bcc: (blind carbon copy) header. That way each
recipient doesn't get to see the full list of recipients in headers as
received, and it prevents the related problems. You may need to alter the
configuration of your mail client to make the Bcc: header available for
completion: contact the Helpdesk for advice.
Can you please ensure that you use this method in future. We could
enforce this at the mail servers, but we would prefer people to do so
If mailing a specific large group is something you are likely to do
regularly, then the best option would be to request the establishment of a
properly managed mailing list.
It doesn't really make sense to "move" recipients from the To: header to
the Bcc: header. To the email system, they are all just recipients.
What goes in those headers is cosmetic only, and need bear no relation to
the actual messsage recipients (but ordinary mail clients usually "do the
right thing" behind the scenes).
In your MTA, you could refuse to accept messages where the To:/Cc: headers
are "too large", for some value. Alternatively you could accept the
message and then just wipe the contents of the To:/Cc: headers (or replace
with something syntactically valid like:
To: many recipients:;
However, generally I would advise against automatic tinkering with message
contents. Choose carrots rather than sticks: after user education, maybe
penalise messages that don't conform (maybe you could hold them on the
queue for manual evaluation and then give the sender some more education,
before releasing them. Repeated delays will annoy them, but they will
learn how to avoid them eventually. Make the delays longer for repeated
offenders!). If the carrot doesn't work over time, use your stick and
refuse to accept them! But what you can get away with depends on your
userbase, and what you can technically do depends on your MTA.
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Jethro R Binks
Computing Officer, IT Services, University Of Strathclyde, Glasgow, UK
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