One of NMIS's main features is that it pings all nodes and maintains a reachability metric which includes response time and ping loss. PING or (Packet InterNetwork Groper) is very powerful for network management and often highly underrated.
In versions of NMIS before NMIS 8.5.6, the PING timeout has been set to 300 milliseconds (ms), which for the majority of networks is no problem, over the last few years, the NMIS development team have seen a number of times where the default of 300ms needed to be raised to 3000ms or higher, to support networks with satellite links, low speed links or just unexplained outages which were false positives.
In NMIS 8.5.6 the default ping time has been set to 5000 ms.
For more details about NMIS and fping read NMIS8 and fping or just ping.
Changing Ping Timeout
The ping timeouts are configured in the NMIS Configuration file Config.nmis. You can edit this from the NMIS GUI using the menu option "System -> System Configuration -> NMIS Configuration".
Then select system and you will get a long list. You will need to edit the ping_timeout and fastping_timeout I would suggest you set them to 5000 (5000 milliseconds).
After this change you will need to restart the fping daemon (from NMIS 8.5.6 the fping daemon will auto restart after a config change), as the root user (or with sudo) run this command: