DenyHosts defaults to sending an email to root whenever it adds an IP address to its blocklist. This can result in a large number of emails being sent to the server admin.
To resolve this issue, login to the server which is sending the notifications via SSH. Edit /etc/denyhosts.conf and look for the ADMIN_EMAIL option. Change its value to be blank:
You may then wish to enable logging of denied IPs so there is a record of when an IP has been blocked. To do this, change the configuration option called SYSLOG_REPORT to:
To make these changes take effect, restart DenyHosts: