Xenosoft in New Haven CT?

Gary Oliver go at ao-cs.com
Thu Feb 25 18:41:51 CST 2016

On 02/25/2016 03:41 PM, Mouse wrote:
>> [...ao.com...]
>> At the point where we finally sold the domain to be rid of this issue
>> (and make a few $) we were processing in excess of *300000* messages
>> a day.  This is for a 7 person company.  It was more than 50% of the
>> email processed by our ISP.  Our DSL router throttled the SMTP
>> requests so we could SOME work done during the day.
> Hm?  You're implying your ISP was handling your mail, but then you
> imply you were handling your own mail.  I'm a little confused.
> The main reason I'm writing, though, is a bit different.
> That there's a company I know that was in a somewhat similar position -
> they were getting so much spam bounce blowback that they were shutting
> off all incoming SMTP during the day to keep the machine up.  I wrote a
> very lightweight SMTP server for them; it accepts connections and talks
> SMTP until it gets a valid recipient, and then - and only then -
> connects through to the real SMTP server and passes protocol both ways.
> It was very good at turning away mail to unknown addresses.  There was
> one time when some host in south-east Asia opened about 100 parallel
> connections and started a dumb-as-rocks dictionary attack.  It turned
> away many tens of thousands of unknown recipients in something like
> thirty seconds, and, even knowing exactly when it happened, I couldn't
> find the blip on our load graphs - it was drowned out by the noise.  If
> I hadn't been reading the logs for other reasons and stumbled across it
> I never would have known it happened at all.
> Obviously, it's of no direct use to you now that you don't hold ao.com
> any longer.  But in case you - or anyone else - is interested, I got
> their approval to open the code up; it's available to anyone who cares
> to fetch a copy.  ftp.rodents-montreal.org:/pub/mouse/misc/mail/shim.
> is the place to look for those interested.
> /~\ The ASCII				  Mouse
> \ / Ribbon Campaign
>   X  Against HTML		mouse at rodents-montreal.org
> / \ Email!	     7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B

They weren't 'handling' it - sorry if I typed something confusing. They 
were merely
noticing the volume of traffic heading to our SMTP servers from their 

Our ISP at that time was a small, local outfit and we knew all the tech 
support folks
personally.  I guess they saw this traffic while trying to analyse why 
there was so
much 'noise' in the data THEY processed locally.

Your described hack sounds like something my 'network admin' did for 
us.  Made some
very light-weight decisions to try and drop as much as possible.  He was 
(is) a Perl GURU,
now working for the ISP mentioned.  Alas, we are no longer with them as 
we are beyond
DSL distance (due to more off-topic noise about our local phone company.)

Our volume is much lighter these days but I'm always trying to improve 
stuff (still
way too much spam) so, thanks.  I will probably grab a copy of what you 
did and see
if it can be of use to us.  *THANKS*

Now back to regular on topic stuff.

-- -Gary

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