User Manual

UPS Network Management Card 3 User Guide9
Watchdog Features
Overview
To detect internal problems and recover from unanticipated inputs, the NMC 3 uses internal, system-wide
watchdog mechanisms. When it restarts to recover from an internal problem, a System: Network Interface
restarted event is recorded in the event log.
Network interface watchdog mechanism
The NMC 3 implements internal watchdog mechanisms to protect itself from becoming inaccessible over the
network. For example, if the NMC 3 does not receive any network traffic for 9.5 minutes (either direct traffic,
such as SNMP, or broadcast traffic, such as an Address Resolution Protocol [ARP] request), it assumes that
there is a problem with its network interface and restarts.
Resetting the network timer
To ensure that the NMC 3 does not restart if the network is quiet for 9.5 minutes, the NMC 3 attempts to
contact the default gateway every 4.5 minutes. If the gateway is present, it responds to the NMC 3, and that
response restarts the 9.5-minute timer. If your application does not require or have a gateway, specify the IP
address of a computer that is running on the network and is on the same subnet. The network traffic of that
computer will restart the 9.5-minute timer frequently enough to prevent the NMC 3 from restarting.
Automatic Logout
By default, users will be automatically logged out of the NMC Web and CLI interfaces after 3 minutes of
inactivity. The default logout time for each user can be adjusted through the web interface:
Configuration > Security > Local Users > Management.
– Click the hyperlink of the user name for the account you want to change.
– Under Session timeout, modify the number of minutes.
Automatic Logout Duration (min)
Default 3
Minimum 1
Maximum 60 (1hr)