Autoresponder Evils?

[Jethro R Binks]

On Tue, 12 Sep 2006, Rick Chadderdon wrote:

> John Rudd wrote (in the thread: Spamcop.net RBL blocking emails by
> mistake?):
> > - autoresponders aren't evil,
> 
> Of course not, not an absolute evil.  But if your autoresponder responds
> to mail from the internet, sending automatic replies to any address it
> sees in the "From:" header, then *your* autoresponder *is* evil - and
> should be banned.  I don't know how you're set up, but if it's possible
> to flood a third party by firing off a bunch of forged messages to your
> mail server, you're set up wrong.  I've seen quite a few people so
> adamant in their defense of autoresponders that they don't bother trying
> to make one that does its job without burdening the rest of the 'net for
> the convenience of the operator.

Well, since you asked.

Most sensible autoresponders will only send one message within a period of 
time to a particular correspondent, so 'flooding' one correspondent is 
impossible (from one autoresponder anyway).

If you want to design a sensible autoresponder, then go read this page 
which I contributed substantially to.  It is written with Exim in mind, 
but the general principles are applicable to any rationally-configurable 
MTA (or one which could run a program to do these checks at SMTP-time):

http://www.exim.org/eximwiki/EximAutoReply

> And, usually, out-of-office and information autoresponders fall into the
> same category.  A significant percentage of the unwanted email that gets
> through my filters comes from autoresponders of one kind or another. 
> Perhaps yours is properly configured and shouldn't be banned...  That
> would be a nice change from what I normally see.

Autoresponders will never go away, and there is no reason why they should.  
However we can significantly minimise their adverse effects by performing 
checks such as those detailed above.  Happy to hear of other suggestions 
for checks.

Jethro.

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Jethro R Binks
Computing Officer, IT Services
University Of Strathclyde, Glasgow, UK