Count Expression Example

In the following example, every ten seconds the CLEAR-Flow agent will request the counter1 statistics from the hardware.

After it receives the counter value, it will evaluate the CLEAR-Flow rule. If the value of counter1 is greater than 1,000,000 packets, the CLEAR-Flow agent will send a trap message to the SNMP (Simple Network Management Protocol) master, and change the ACL (Access Control List) acl_rule1 to block traffic (acl_rule1 is modified to a deny rule).

Since there is no period configured for the snmptrap statement, the message is sent only once.

entry acl_rule1 {
if {
destination-address 192.168.16.0/24;
destination-port 2049;
protocol tcp;
} then {
count counter1;
}
}
entry cflow_count_rule_example  {
if { count counter1 > 1000000 ;
period 10 ;
}
Then {
snmptrap 123 "Traffic on acl_rule1 exceeds threshold";
deny acl_rule1;
}
}