I wrote a script which continually scanned /var/log/messages for "invalid user" entries logged by sshd, and did a
iptables --append INPUT --source srcaddr -j DROP
which was removed after 10 minutes. Most of the scanners never came back after the 10 minutes.
Copyright © 2017, Eklektix, Inc.
Comments and public postings are copyrighted by their creators.
Linux is a registered trademark of Linus Torvalds