[Top] [All Lists]

Re: [ietf-smtp] You can't hurt a computer's feelings

2013-03-03 08:19:30
At 6:36 PM -0500 2/28/13, John R Levine wrote:

 It'd be interesting.

Here's the answer I got:

At 3:05 PM -0500 3/1/13, David Ross wrote:
It would depend on how many connections you have allocated to regular SMTP and how many to authenticated SMTP.

One EIMS server I have in a small business has both set to 20. Server has been up since Feb 23 and the max connections to date are 7 regular and 4 authenticated at any one time. And with a limit of 20 on the regular SMTP connections I've never seen it hit 20 for at least 5 or more years.

I suspect this is not as much of an issue now that computers can more easily handle a lot of connections and spammers are likely better at not flooding any one server with connections. I suspect the later also depends on the number of domains hosted.

Most of the heavy attacks I see these days come in waves where they fire off from 100 or so IPs in a /24 each with a different domain as the sending entity. Spread over a few hours with under 5 connection attempts per IP.

The office I mentioned with 2 domains and 20 people sees one or two of these a day.

Randall Gellens
Opinions are personal;    facts are suspect;    I speak for myself only
-------------- Randomly selected tag: ---------------
...All repairs tend to destroy the structure [of the software], to
 increase the entropy and disorder of the system.  Less and less
 effort is spent on fixing original design flaws; more and more is
 spent on fixing flaws introduced by earlier fixes.  As time passes,
 the system becomes less and less well-ordered.  Sooner or later the
 fixing ceases to gain any ground.  Each forward step is matched by a
 backward one.  Although in principle usable forever, the system has
 worn out as a base for progress.  [...] Systems program building is
 an entropy-decreasing process, hence inherently metastable.  Program
 maintenance is an entropy-increasing process, and even its most
 skillful execution only delays the subsidence of the system into
 unfixable obsolescence.
                            --Fred Brooks in _The Mythical Man Month_
ietf-smtp mailing list