test.cpp

#include <Ethernet.h>

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
byte ip[] = { 10, 0, 0, 177 };
byte gateway[] = { 10, 0, 0, 1 };
byte subnet[] = { 255, 255, 0, 0 };

Server server = Server(23);

void setup() {
  Ethernet.begin(mac, ip, gateway, subnet);
  server.begin();
}

void loop()
{
  Client client = server.available();
  if (client == true) {
    byte v = client.read();
    analogWrite(9, v);
  }
}