CentOS - Jul 2017 - I found this interesting: amount of evil traffic on the internet

I've just done a little "study" (well, nothing quite that
pretentious)
of the traffic hitting my router, that gets DROPped the router's
firewall. there is a surprisingly (to me, at least) enormous amount of
it. over about the last 3 weeks, it has dropped over 65,000 connection
attempts.

I finally got around to figuring out how to have the router's logging
mechanism connect to the rsyslog on my Centos workstation, so I can 
collect a large body of log entries to review. previously I could see
only a few hundred at a time, since the router doesn't have huge
storage.

Here's just the first few items from the list, listed as port number
ordered by total number of hits:

DPT=3343   8859
DPT=23     7872
DPT=3344   5984
DPT=6      4925
DPT=68     4291
DPT=9      2625
DPT=3291   2524
DPT=32915  2523
DPT=143    2467
DPT=1433   2377
DPT=445    2037
DPT=33441  1544
DPT=33442  1522
DPT=33440  1511
DPT=33434  1511
DPT=33435  1487
DPT=33436  1486
DPT=33437  1476
DPT=33439  1458
DPT=33438  1439
DPT=80     1068
DPT=33443  1060
DPT=5060   948

Some of those are ports I've never been aware of, such as 3343, which
/etc/services lists as "ms-cluster-net". Obviously something on MS
systems, and apparently a lot of mal-dudes think it's a great port to
hit on, in case it might just happen to be wide open.

then there's port 23 (telnet) which at 7872 hits is ample evidence for
why everybody who knows anything says to NEVER put a system on the
internet with an open telnet port.

sigh.

Then, even after all this garbage is filtered out, there is another HUGE
pile of things hitting my mail server that get filtered out by a variety
of filtering techniques including but not limited to greylisting email.
(BTW, greylisting was by far the most effective of all the filtering
techniques I've found for dropping spam before it ever gets into my
mail system. For mail that does get in, SpamBayes works great, once one
figures out how to configure it.)

If any of you don't believe that the 'net is populated by evil beings,
let this be a lesson to ye!

Thanks for your time!

Fred
-- 
---- Fred Smith -- fredex at fcshome.stoneham.ma.us
-----------------------------
   "For the word of God is living and active. Sharper than any double-edged
   sword, it penetrates even to dividing soul and spirit, joints and marrow; 
              it judges the thoughts and attitudes of the heart."  
---------------------------- Hebrews 4:12 (niv) ------------------------------