Re: How to patch?

[Mike Roest]

Andrea Prunic wrote:
<snip unrelated original message>
OK, when we're on the subject of patches...

I have a big problem at the moment with a couple of qmail servers I'm
responsible for:
when I receive a message from system bad.system.com, where envelope
sender and/or From: field are from [EMAIL PROTECTED], directed to
another [EMAIL PROTECTED], my.good.system.com receives the
message, even if bad.system.com made the connection.
Ok this is normal smtp behaviour.
Now, I did put up a correct control/rcpthosts only for
my.good.system.com, and in /etc/tcp.smtp.cdb I have allowed connectin
for anybody, and relaying only for clients from IP's of my.good.system.com.
ok this is fine

<snip extra explanation>
As you can see, I can send a message pretending that I am from
my.good.system.com to a user at my.good.system.com, even though I am
coming from bad.system.com....
This is a limitation of the SMTP protocol.  There really is nothing you 
can do for this.
So, how can a man plug this hole? I don't see anything of that kind
mentioned in any instructions for qmail, only basic thing with rcpthosts
(which is valid for the above scenario) and tcp.smtp.cdb (which is also
OK)...
To plug this hole you really will need to redesign the internet email 
system from the ground up.  While you're at it want to fix it so no more 
spam get's into my mailbox.
I suspect that there is some patch for this, but don't know which one,
that can also be applied to qmail with the LDAP patch.
I've not seen a patch for this behaviour as it's basically just a hole 
in the way SMTP was implemented

On a seperate note in the future please don't reply to an existing 
thread with a unrelated question.  It messes up the archives and plays 
havok with threaded mail readers.

--Mike