Troubleshooting DenyHosts
DenyHosts, a software which blocks malicious ssh attempts, is installed by default on all of our managed servers. To check if any authentic hosts are blocked from sshing you can run:
sudo cat /etc/hosts.deny
If there are any blocked hosts you will see a section like below (111.222.333.444 is a placeholder IP):
# DenyHosts: Tue Aug 7 11:53:04 2018 | sshd: 111.222.333.444 sshd: 111.222.333.444
IGPP HelpDesk is automatically notified of any blocked hosts. If you would like to be added to the email list for blocked IPs on your managed server, send a request to igppticket@ucsd.edu.