ESXi supports four serial port modes.

There are four serial port modes in ESXi:

Logging mode – Logging mode is the default mode in a debug build. Logging mode sends the vmkernel.log over the serial port.

GDB mode – Use GDB mode for dedicated debugging.

Shell mode – Shell mode is the shell port access, which is similar to SSH.

DCUI mode – DCUI mode is a Direct Console User Interface. This is the user interface that is displayed when you boot ESXi using a monitor.


Only COM1 and COM2 ports are supported. USB serial or PCI serial cards are not supported.