Advisor
ProfessorICMP is a terrible way for the Collector to determine “Host Dead” status. Better would be if any DataSource is able to collect data from it. If data can be collected, the host isn’t dead.
ICMP itself seems to be fine now, actually. The problem that persists is SNMP when an intermediate stateful inspection engine (firewall) invalidates sessions. UDP is stateless, but SNMP uses a session ID most modern firewalls recognize. Once the session ID is broken, LM stops working since the developers chose to blindly use the same session ID indefinitely. My guess is with the new collector code they periodically refresh the session ID so it eventually recovers rather than trigger a new session after a failed poll or two. The right way is very often not the way these developers roll, sadly,