PLC Networking, Security, and Backup Services
Industrial Networking in the Lowcountry
CloudCentric is a managed IT provider in Mount Pleasant, South Carolina, serving businesses across Charleston and the Lowcountry. You can reach us at (844) 422-7000.
We support Allen-Bradley/Rockwell and Siemens PLCs on a UniFi network backbone. The work covers controller networking: IP addressing, VLANs, switch ports and the links between PLCs, HMIs, drives and engineering workstations.
Unmanaged switches in PLC panels are replaced with managed UniFi DIN-rail switches that report port status to one console.
CloudCentric holds no partner, certification or authorised-integrator status with Rockwell Automation, Allen-Bradley or Siemens; the brand names identify the equipment worked on.
Managing EtherNet/IP and PROFINET Traffic
Allen-Bradley/Rockwell controllers communicate on Ethernet over EtherNet/IP; Siemens controllers use PROFINET and S7comm.
EtherNet/IP I/O data can be sent as UDP multicast, and ODVA, the body behind EtherNet/IP, recommends switches with IGMP snooping to keep that traffic from spreading across the network. UniFi industrial switches support IGMP snooping and an IGMP querier.
PROFINET real-time I/O frames travel directly in Ethernet frames (EtherType 0x8892) without TCP/IP, so PROFINET devices and their controller share one Layer 2 network with no router between them.
Isolating Controllers from Internet Attacks
Connectivity work includes removing PLCs from the public internet and replacing modems with VPN access through the firewall.
CISA advisory AA26-097A names Allen-Bradley CompactLogix and Micro850 and Siemens S7-1200 among the controllers attackers reached through the internet. Furthermore, AA26-231A (2026-08-19) covers Siemens S7-200, S7-300, S7-400, S7-1200 and S7-1500 controllers.
CISA lists ports 44818 and 2222, which EtherNet/IP uses, among the controller ports seen in attacks; both are kept off the internet. Siemens S7 controllers use S7comm over TCP port 102, which CISA asks owners to block at the perimeter.
Access Control and Configuration Security
Default passwords on controllers and HMIs are changed, as CISA and the Coast Guard rule both ask.
CISA advises keeping a controller's physical mode switch in Run, and using Program or Remote mode only for updates.
For Siemens controllers CISA advises enabling password protection and protection levels, and limiting TIA Portal or STEP 7 access to listed engineering workstations.
Program Backups and Restoration
For program backups, a copy of each controller's program and configuration is kept offline and tested, so a controller can be restored after a failure or a changed password.
CISA's 2026-07-30 alert asks water systems to keep a known clean backup of each PLC image before or after disconnecting it from the internet.
CISA advisory AA26-097A asks owners to verify backups are free of malicious logic before restoring, and to compare running logic against known-good versions.
Network Limits and Hardware Boundaries
The UniFi industrial switches list STP and RSTP only; they support no ring redundancy protocol such as ERPS, MRP (PROFINET) or DLR (EtherNet/IP), so redundancy comes from dual power inputs and paired uplinks, not a ring. Ring topologies built on PROFINET MRP or EtherNet/IP DLR stay on switches that support those protocols.
No UniFi page says the gateway firewall or IDS/IPS understands industrial protocols such as Modbus/TCP, EtherNet/IP, S7comm, PROFINET or DNP3; rules between zones are written by address and port.
No UniFi product carries a hazardous-location rating (Class I Division 2, ATEX or IECEx); UniFi gear goes in unclassified rooms, never in fuel, dust or chemical classified areas.