Release notes say HostDos Problems Corrected in 8.31.01.0005 Introduced in Version: Enabling the HostDoS portScan feature mistakenly filters inbound packets on port 22 when SSH is enabled. HostDoS should only filter these packets when SSH is disabled. This may render the switches SSH server inoperable, and the DoS attack detection logic may produce false positives. A workaround is to not enable HostDos portScan, or to enable it but with a relatively high portScan rate limit. Another workaround is to disable and then re-enable SSH (via a Telnet or console connection). However, the problem will return following a system reboot.
Command to increase rate hostDos Portscan rate 10 per-second