tcpdump:
tcpdump -i any -nn host XX.XX.XX.XX
do something for each line in file:
for i in $(cat hosts) ; do echo $i ; done
regenerate ssh fingerprint:
rm /etc/ssh/ssh_host_*
ssh-keygen -q -f /etc/ssh/ssh_host_rsa_key -N '' -t rsa
ssh-keygen -q -f /etc/ssh/ssh_host_dsa_key -N '' -t dsa
ssh-keygen -q -f /etc/ssh/ssh_host_ecdsa_key -N '' -t ecdsa
ssh-keygen -q -f /etc/ssh/ssh_host_ed25519_key -N '' -t ed25519
systemctl restart ssh
convert putty generated public key to openssh public key
ssh-keygen -i -f keyfile.pub > newkeyfile.pub