Method and apparatus for debugging an operating system kernel. A server data processing system includes a debugger control component and a network interface card that implements a protocol stack, including layers from a physical layer through an application layer. The network interface card further includes a debugger network component. Debugger control messages received by the network interface card are directed to the debugger network component. The debugger network component communicates the debugger messages to the debugger control component in the kernel, and the debugger control component performs debugging operations in response to the debugger messages.