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Topic: Make arduino visible to modem for port forwarding? (Read 971 times) previous topic - next topic


I've got it on and I need to forward it's port (84) but since it is currently invisible to the modem, I can't select it to send the port 84 traffic to. Can someone give me a hand here? I'll post the code if you think it will help..

Here's the code:
Code: [Select]

#include <SPI.h>
#include <Ethernet.h>
#include <Servo.h>

byte mac[] = {
  0x90, 0xA2, 0xDA, 0x00, 0x32, 0x46 }; //physical mac address
byte ip[] = {
  192, 168, 0, 13 }; // ip in lan
byte gateway[] = {
  192, 168, 0, 1 }; // internet access via router
byte subnet[] = {
  255, 255, 255, 0 }; //subnet mask
Server server(84); //server port

String readString, servo1;

Servo myservo1;  // create servo object to control a servo

void setup(){

  //start Ethernet
  Ethernet.begin(mac, ip, gateway, subnet);

  //enable serial data print
  Serial.println("bot21"); // so I can keep track of what is loaded

void loop(){
  // Create a client connection
  Client client = server.available();
  if (client) {
    while (client.connected()) {
      if (client.available()) {
        char c = client.read();

        //read char by char HTTP request
        if (readString.length() < 100) {

          //store characters to string
          readString += c;

        //if HTTP request has ended
        if (c == '\n') {


          //readString looks like "GET /?-1500-1500 HTTP/1.1"

          if (readString.length() >0) {

            servo1 = readString.substring(7, 11);


            int n1;

            char carray1[6];
            servo1.toCharArray(carray1, sizeof(carray1));
            n1 = atoi(carray1);



          //now output HTML data header
          client.println("HTTP/1.1 204 Zoomkat");
          //stopping client

          //clearing string for next read



The last three DSL modems I had have had the same problem.  I looked closely and there was a check box that let me enter the ip address directly.  I first limited the DSL address pool to - .45 and placed my arduinos above 200 (I don't have a reason for this, just did it) and the checked the box.  I was then able to forward any one of the arduinos.
Trying to keep my house under control http://www.desert-home.com/

Nick Gammon

I've got it on and I need to forward it's port (84) but since it is currently invisible to the modem, I can't select it to send the port 84 traffic to.

There's no particular reason it should be visible to the modem (as you put it) because you are not using DHCP. Just type the address in ( and forward port 84 to that.
Please post technical questions on the forum, not by personal message. Thanks!

More info:


You probably need to give more information on your "modem" to get better help.
Google forum search: Use Google Search box in upper right side of this page.
Why I like my 2005 Rio Yellow Honda S2000  https://www.youtube.com/watch?v=pWjMvrkUqX0

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