I have an ISA570 firewall setup with 2 internet connections coming in. I have both ports being monitored in PRTG. Once in a while I get a line that goes down, but PRTG never seems to recognize the connection as down. It seems to only show the connection as down when the port is physically disconnected. To find the connection, I normally have to manually refresh the sensor and look for "IN" traffic to be 0kb. This is how I know which line is down. Currently, I just had Errors In & out selected under Traffic specfic and now I enabled Discards In & Out, not sure if that will help. Let me know.
Thanks in advance.