RE: Dropping connection instead of returning 400

> Christopher,
>
>  It seems like such a trivial measure that I don't think breaking the
> spec is worth it. You seem to be concerned about the information
returned... well just return less. Don't 'break the spec' for
> something so trivial.
Doing this in accordance to the spec in a pipeline is a bit more
complicated.  I am working on a blog entry that explains some of the
issues of proxying pipelines.  The primarily problem is determining the
number of requests you'll send to server before receiving a reply. 
Information needs to be buffered and queued in the proxy which is a
potential area for overrun failures.  This is not required by straight
through proxies like stunnel.  I'm going to implement this since everybody
is so keen on this, but I'm going to continue make dropping connection
optional.

I talked this issue over with a friend of mine that works at an anti spam
company, and they do exactly what I am proposing.  If they determine the
message is spam they drop connection immediately regardless of the SMTP
spec.  Also I see this as a similar to rejecting TCP/IP packets (ie
dropping them) which is common in TCP/IP firewalls, but not as friendly as
a denying them with a returned ICMP packet.


Christopher Baus
http://www.baus.net/