Internet-Security.com TCP port 10004 details

Lantronix serial-to-Ethernet device servers (e.g., EDS4100/EDS2100, UDS/ETS/SCS series) map each serial channel to a TCP port; by default, serial port 4 is accessible on TCP 10004 for raw socket/RFC2217 connections.
In the field, these ports are used to tunnel console/serial traffic for equipment like PLCs, RTUs, and network gear via the Lantronix box.
Security note: Exposed Lantronix ports (10001–10004) are routinely scanned and have been abused to interact with attached serial devices when authentication is weak or disabled.

TCP 10004