[plug] re: Email rules

Bret Busby bret at busby.net
Wed Feb 20 12:00:25 WST 2008

On Wed, 20 Feb 2008, Gavin Chester wrote:

> On Tue, 2008-02-19 at 12:56 +0900, Jon Miller wrote:
>> Like to know if anyone knows if there are rules in either Postfix or
>> SA that prevents mail from entering the system if in the headers the
>> TO: and FROM: are the same.  I seem to think that there is a rule that
>> states if the two fields has the same information and the mail
>> originated from the Internet it was to either drop of delete the mail.
> So are you saying that when I send emails to a group of recipients in
> the way I described before (ie, from me to me, with them in the BCC)
> that you and others will treat that as spam? Why? I thought it good
> netiquette to do it that way and what harm could it possibly do the
> recipient since I'm not obscuring my address? I would shudder to think
> you might block ALL email that does that regardless of originating
> address :-/
> Gavin

As is usual with mailing lists, some people will agree, and some people 
will disagree.

I think that it is bad "netiquette" to send emails that ahow a To 
address that is the same as the From address.

About 95-99% of that type of email that I receive, are malicious.

However, unfortunately, the secretary of one organisation of which I am 
a member, uses that method for distributing email messages.

I believe and suggest that a far more responsible method, would be to 
use a mailing list; either an announce only mailing list, or a mailing 
list to which subscribers may post. It is easy enough to require manual 
approval of subscriptions.

Using a mailing list, gives a To address that is different to the From 
address, and filtering on mailing list header fields (such as the 
Reply-To address, for mailing lists where people reply both to previous 
posters in a thread and to the mailing list, making using just the To 
field, an unreliable parameter for filtering), is simple enough.

I also have family members who from time to time, use a To address of 
"undisclosed recipients". Whether they stil do that I do not know, as, 
due to the volume of malicious email messages that use that To address, 
all such email mesages are automatically deleted. That is one of the 
filters that I have set up in PINE, rather than in either postfix or 

*** Perhaps it is procmail at which you should be looking, for 
filtering, rather than postfix, Jon? That is, if you can get the 
procmail filtering working. I have not yet been able to get procmail 
filtering working, on our mailserver.

Bret Busby
West Australia

"So once you do know what the question actually is,
  you'll know what the answer means."
- Deep Thought,
   Chapter 28 of Book 1 of
   "The Hitchhiker's Guide to the Galaxy:
   A Trilogy In Four Parts",
   written by Douglas Adams,
   published by Pan Books, 1992


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