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How to diagnose ping problems

You can use the Data ONTAP ping throttling mechanism and its ip.ping_throttle.drop_level option to help avoid denial-of-service attacks that can occur when using ICMP.

The ping throttling mechanism is active in intervals of 1 second. If the number of ICMP echo and reply packets that the storage system receives in a one-second interval exceeds the ping throttling threshold, the storage system drops all subsequent packets that are received within that one-second interval.
Note: Regardless of whether the ping throttling threshold has been reached, clients that send more than 16 packets per second to a storage system might experience packet loss. To allow clients to send more than 16 packets per second, you must disable ping throttling.

If your storage system supports a very large number of CIFS clients that use ICMP pings to determine CIFS shares accessibility, you can increase the ping throttling threshold value in the ip.ping_throttle.drop_level option.

If a large number of CIFS clients are experiencing temporary or persistent unavailability of the storage system, you should check to see if the ping throttling threshold has been exceeded for the storage system. If so, you can increase the ping throttling threshold value.