Ethernet Shield DHCP Chat Server

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1/*
2
3 DHCP Chat  Server
4
5 A simple server that distributes any incoming messages to all
6
7 connected clients.  To use, telnet to your device's IP address and type.
8
9 You can see the client's input in the serial monitor as well.
10
11 Using an Arduino Wiznet Ethernet shield.
12
13 THis version attempts to get an IP address using DHCP
14
15 Circuit:
16
17 * Ethernet shield attached to pins 10, 11, 12, 13
18
19 created 21 May 2011
20
21 modified 9 Apr 2012
22
23 by Tom Igoe
24
25 modified 02 Sept 2015
26
27 by Arturo Guadalupi
28
29 Based on ChatServer example by David A. Mellis
30
31 */
32
33#include <SPI.h>
34#include <Ethernet.h>
35
36// Enter a MAC address and IP address for your controller below.
37// The IP address will be dependent on your local network.
38// gateway and subnet are optional:
39byte mac[] = {
40
41  0x00, 0xAA, 0xBB, 0xCC, 0xDE, 0x02
42};
43
44IPAddress ip(192, 168, 1, 177);
45
46IPAddress myDns(192, 168, 1, 1);
47
48IPAddress gateway(192, 168, 1, 1);
49
50IPAddress subnet(255, 255, 0, 0);
51
52// telnet defaults to port 23
53
54EthernetServer server(23);
55
56bool gotAMessage = false; // whether or not you got a message from the client yet
57
58void setup() {
59
60  // You can use Ethernet.init(pin) to configure the CS pin
61
62  //Ethernet.init(10);  // Most Arduino shields
63
64  //Ethernet.init(5);   // MKR ETH shield
65
66  //Ethernet.init(0);   // Teensy 2.0
67
68  //Ethernet.init(20);  // Teensy++ 2.0
69
70  //Ethernet.init(15);  // ESP8266 with Adafruit Featherwing Ethernet
71
72  //Ethernet.init(33);  // ESP32 with Adafruit Featherwing Ethernet
73
74  // Open serial communications and wait for port to open:
75
76  Serial.begin(9600);
77
78  while (!Serial) {
79
80    ; // wait for serial port to connect. Needed for native USB port only
81
82  }
83
84  // start the Ethernet connection:
85
86  Serial.println("Trying to get an IP address using DHCP");
87
88  if (Ethernet.begin(mac) == 0) {
89
90    Serial.println("Failed to configure Ethernet using DHCP");
91
92    // Check for Ethernet hardware present
93
94    if (Ethernet.hardwareStatus() == EthernetNoHardware) {
95
96      Serial.println("Ethernet shield was not found.  Sorry, can't run without hardware. :(");
97
98      while (true) {
99
100        delay(1); // do nothing, no point running without Ethernet hardware
101
102      }
103
104    }
105
106    if (Ethernet.linkStatus() == LinkOFF) {
107
108      Serial.println("Ethernet cable is not connected.");
109
110    }
111
112    // initialize the Ethernet device not using DHCP:
113
114    Ethernet.begin(mac, ip, myDns, gateway, subnet);
115
116  }
117
118  // print your local IP address:
119
120  Serial.print("My IP address: ");
121
122  Serial.println(Ethernet.localIP());
123
124  // start listening for clients
125
126  server.begin();
127}
128
129void loop() {
130
131  // wait for a new client:
132
133  EthernetClient client = server.available();
134
135  // when the client sends the first byte, say hello:
136
137  if (client) {
138
139    if (!gotAMessage) {
140
141      Serial.println("We have a new client");
142
143      client.println("Hello, client!");
144
145      gotAMessage = true;
146
147    }
148
149    // read the bytes incoming from the client:
150
151    char thisChar = client.read();
152
153    // echo the bytes back to the client:
154
155    server.write(thisChar);
156
157    // echo the bytes to the server as well:
158
159    Serial.print(thisChar);
160
161    Ethernet.maintain();
162
163  }
164}