[Mailman-Users] Make sure that only our newsletter can be delivered to a mailing-list that is not moderated

Brad Knowles brad at stop.mail-abuse.org
Fri Aug 27 15:01:25 CEST 2004

At 2:40 PM +0200 2004-08-27, Jacob Friis Larsen wrote:

>>>  How can we secure our list server?
>>  Just add all the necessary addresses to the list of addresses that
>>  are allowed to post to the list. Moderate all other senders.
>  Wouldn't it be too easy for someone to change their sender address and
>  get their spam out to our customers?

	That would be a very real risk.  One thing you could do is make 
the Mailman server sit behind a firewall, and accept incoming 
connections only from your local network.  This would mean that 
someone would have to be able to get access to one of your internal 
machines in order to send out stuff as your process, in addition to 
spoofing the address.

	You could even go so far as to set it up so that it only listens 
to the IP address, which means that all traffic would have 
to be generated locally on the machine itself, and it wouldn't accept 
traffic from any other system, even if it was on the same network.

	Regretfully, when it comes to security, what Mailman provides is 
relatively minimal.  It will validate the sending address, but it 
can't prevent anyone from spoofing it, etc....

	With luck, we might be able to address this in Mailman3, and make 
it capable of using strong cryptographic checks for things like this. 
But that day is not here yet, and it may be a very long time in 

Brad Knowles, <brad at stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

   SAGE member since 1995.  See <http://www.sage.org/> for more info.

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