[Mailman-Users] list address in From: line post message to closed list

Steve Lindemann steve at marmot.org
Thu Apr 3 23:43:16 CEST 2008

Dragon wrote:
> Steve Lindemann sent the message below at 12:18 4/3/2008:
>> The problem - when the list email address is (spoofed) in the From: line
>> (as well as being on the To: line) the message posts to the list.  The
>> ability to post to the list is supposed to be restricted to only list
>> members.  The list address is not in the list of list members.
>> Is this normal?  I checked the config and there did see anything to
>> allow this behavior there.  Is the list email address automatically
>> considered to be a member of the list?  I can always block it in
>> "privacy options->sender filters", but should that even be necessary?  Help!
> ---------------- End original message. ---------------------
> This seemed rather strange to me too so I decided to test it on my 
> server. I have 2.1.10b3 installed from source on a Redhat machine. My 
> list is configured for posts from non-members to be discarded.
> I sent a message to one of my lists using the list address in the 
> From: header. The message was discarded as I expected it would be and 
> I confirmed this by an entry in the vette log.
> So it works on my installation as I expect it would. The question now 
> is, what is the difference between my source install and your 
> installation. Are you using a cPanel or Plesk version, or a version 
> installed from somebody else's package maybe through yum or something similar?
> Are you certain that the message was distributed via the list?
> Is it in the list archive?
> Can you match the message ID to one in the post log?
> If you can see it in the archive and post log then it did get 
> processed through mailman. If not, perhaps it was BCC'ed to your 
> address or there is something else going on with your MTA.
> Dragon

I'm running version 2.1.9, installed from a tarball on a Dell server 
running CentOS 5.  I administer from the command line and thru the web 
interface.  It's a pretty basic install.

I went thru the logs and saw the message hit our email server 
(originally from 5850-260-1-62.dialup.samtel.ru), it gets passed to 
mailman and I see the  post entry showing it's arrival into mailman then 
then smtp entry showing it's delivery back to the email server.  I 
confirmed the delivery to the 144 recipients (fortunately this is a 
small list) in the mail log.  I am one of the recipients on this list, 
but in my case spamassassin flagged the message and it gets filtered away.

I just widened my search thru the mailman logs and noticed some other 
lists (in the vette log) holding messages for moderation with the list 
email in the From: line.  So it does appear to be something in this 
specific list that's misconfigured.  I'm off to poke around the config 
again but I'd be very interested in any suggestions about what I might 
be looking for!?  My first pass thru the config I was looking for 
something that would allow this to happen and didn't see it.

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