Messaging Allen Bradley Via Firewall

I have a need to send some PLC message's from one PLC, controllogix on one network (PLC A - 172.18.239.22) to a PLC 5 on DH+ via a DH+/Ethernet bridge on another network (GW - 172.18.40.112). The is a firewall between the two networks.

Which ports are needed by the MSG instructions that need to be opened in the firewall? I have done some reading, and some things say TCP 2222 or TCP/UDP 44818. Is this all that is required? Do I set up the MSG as usual (i.e. DH+ message CIP path to the DHRIO card then DH+ node address).

You need to open TCP Port 44818 for the MSG instruction to work. Everything else in the message should be unaltered.

TCP Port 2222 is for the old PLC-5E/SLC-5/05 proprietary Allen-Bradley Ethernet network, and there is no UDP involved in a conventional MSG instruction from controller-to-controller.

Will do.
Thanks for your help.