I am trying to make my Arduino visible on the internet. I have a Linksys router and have programmed a port forward from external to internet (external for example 123 pointet to internal 80) unfortunately nothing happens when I type my Ip-adress followed by :123 - nothing happens. If i test my ip-adress i get my NAS server, I think it is responding on port 80 (?)

How can I change Arduinos port to a different one 8090 for example? (I have tried the example code but then the Arduino does not show ip internal on its IP dress ( The router is programmed to forward xx.xx.xx.xx:123 to 8090 - nothing happens.

kind regards Karsten

Maybe the router firewall?

Depending on just where you are trying to access your gadget from, you may also find your ISP is the problem - many of them block things like port 80 from home networks to prevent people from setting up servers at home.

THX for your answers.

I am trying to get to my network by using my mobile.

If I only type the IP address I get my NAS server, my NAS is on port 80 :-)

If I add :123 or another port I get nothing.


#include <SPI.h>
#include <Ethernet.h>
#include <DHT11.h>
#include <RealTimeClockDS3231.h>

#define DHT11PIN_1 49
dht11 DHT11; //?? Sensor_2 needed?
int chk, Sensor_2;
// RTC_DS3231 rtc;
byte mac = { 0x90, 0xA2, 0xDA, 0x00, 0x19, 0x8D };
EthernetServer server(7575); //Works only if this is changed to 80 :-/
EthernetClient client;

const int numPins = 5;
int pins = {3, 4, 5, 12, 13};
int pinState = {0, 0, 0, 0, 0};
char line1[100];
char buffer[100];
char formatted = “00-00-00 00:00x”;