4-11
4 Determining IP Addresses
CJ-series EtherNet/IP Units Operation Manual for NJ-series CPU Unit (W495)
4-3 Private and Global Addresses
4
4-3-2 Using a Private Address for the EtherNet/IP Unit
Conditions for Communications Applications
If the EtherNet/IP Unit uses a private address, you can use explicit message communications ser-
vice under the following conditions.
• The explicit message communications service can be executed on the intranet between Ether-
Net/IP Units with private addresses only.
• A device such as a personal computer (CIP applications including the Network Configurator) can-
not connect online and communicate over the Internet with an EtherNet/IP Unit that has a private
address. Explicit message communications are also not possible over the Internet between Ether-
Net/IP Units with private addresses.
Precautions for Correct UsePrecautions for Correct Use
Network Security and Firewalls
To set up an intranet through a global address involves network security considerations. Be sure
to consult with a network specialist in advance and consider installation of a firewall. After a fire-
wall has been set up by a communications company technician, there may be some applications
that cannot be used. Be sure to check first with the communications company technician.
4-3-2 Using a Private Address for the EtherNet/IP Unit
● Intranet
CIP client on a
computer, such as
Sysmac Studio or
Network Configurator
Ethernet (EtherNet/IP)
Ethernet (EtherNet/IP)
IP router
● Intranet
IP router
Controller
Controller
EtherNet/IP Unit: Private address
EtherNet/IP Unit: Private address
Communications in
intranet
Communications in intranet
Explicit message
CIP client on a computer,
such as Sysmac Studio
or Network Configurator
Firewall
● Internet
EtherNet/IP Unit: Private address
Communications in
intranet
Firewall
Explicit message
Controller