I don't know what of our tools you, our readers, use on a regular basis, but one of the things, I like to look at first when I login to isc.sans.edu is the Top 10 Ports by Unique Sources chart. This suggests coordinated (think botnets) scanning. So, I was really shocked to see port 81 had jumped up to 2nd position just behind all the Mirai-ish port 23 scanning. Take a look at the port 81 chart. If any of our readers have any insight into what is going on here since 16 Apr, plase let us know.

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Jim Clausing, GIAC GSE #26
jclausing --at-- isc [dot] sans (dot) edu

I'll be teaching FOR610 in June, Sept, and Oct. See my schedule here: https://www.sans.org/instructors/jim-clausing