Hi to All I want to write a very simple Code for Embed Platform (LPC 1768) And I have Problem I connect the borard (with rj45) to a switch . my laptop is connected too I write and test the following code : ================================================================= #include "mbed.h" #include "EthernetInterface.h" DigitalOut m_led(LED2); Ethernet eth_m; int main() { char buf[0x600]; // 1536 m_led = 1; EthernetInterface eth; eth.init(); //Use DHCP eth.connect(); printf("IP Address is %s\n", eth.getIPAddress()); m_led = 0; if (eth_m.link()) { printf("online\n"); } else { printf("offline\n"); } while(1) { int size = eth_m.receive(); if(size > 0) { eth_m.read(buf, size); printf("Destination: %02X:%02X:%02X:%02X:%02X:%02X\n", buf[0], buf[1], buf[2], buf[3], buf[4], buf[5]); printf("Source: %02X:%02X:%02X:%02X:%02X:%02X\n", buf[6], buf[7], buf[8], buf[9], buf[10], buf[11]); } wait(1); } } ================================================================= but when I want to connect to the LPC throw Laptop (By hercules terminal whit LPC's IP and Port 23) it shows me Error 10061 !! Can you Help me ?? I want a simple test for send and Recieve with TCP protocol.