User Documentation

Version 1.2 / August 2020 Page 86 / 102
►Now define the criteria for investigating an IPv4 packet
(check for Modbus communication = TCP/502) .
Note: Use always wild character * for source port because
it will be created dynamically by the sender (to be used for
unique re-addressing of an answer packet by a recipient).
►Click ‘Next’.
►Select ‘Auto’ for Connection control (Packet filter acts as
a stateful inspection firewall and recognizes/allows auto-
matically an answer based on an initiated request).
►Click ‘Next’.
►No signal check and setting.
►Click ‘Next’.
►Now select action (allow) related to the previous defined
rules.
►Add a name for this rule (here Modbus_Allow).
►Click ‘Next’.
Now the new rule “Modbus_Allow” is defined inside of the
rule-set container. We do not need to add another rule.
►Add a description text for this rule-set.
►Click ‘Next’.
►Click Close