this is seen for monit 5.4 and also monit 5.19 In trying to use the ICMP type echo / ICMP ping functionality. We are using the ping functionality to check accessibility of another machine. If there happens to be another set of machines on the network that are using an ICMP ping of a size smaller than what monit uses, monit sees the ping reply and complains about the reply being too small. For example:
[EDT Jun 27 13:58:51] error : ICMP echo response for 169.254.99.1 1/1 failed -- received 40 bytes, expected at least 48 bytes
The response in this case is meant for a different address, yet it causes a failure for my check condition. The monit code should not treat the small reply as being a failure when it is not for the desired address. The address check should be performed before the size check.