switch to prtg problem

[Roza12]

Hi Guys 

i have problem regarding to customer switches WS-C3650

1- from firewall--> i can ping prtg , switches

2- from switches --> i can't ping prtg, firewall

3- from prtg ---> i can ping all firewall, switches

and i'm receiving prtg alarms regarding to snmp errors i've checked the setting and nothing changed 

and till now i can figure out what is the real cause of the problem

so please any thoughts, ideas 

Thanks 

[pieterh]

how is your network setup? please provide more info

is the firewall between the switch and prtg?

then check logging on the firewall to see packets are received and forwarded.

NB! most firewalls by design do not respond to ping if not configured to do so.

is the switch in the same subnet as the prtg? 

"nothing has changed" -> you did not (yet) find what has changed, it may be something simple like windows-update on the prtg host?