可以通過以太網屏蔽連接，但不能在我的arduino上使用MQTT時連接

Question

我一直試圖通過MQTT從我的Arduino發送消息到我的亞馬遜網絡服務器。以下代碼連接以太網客戶端，但不連接MQTT客戶端。爲什麼我的MQTT客戶端不能連接？

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

byte mac[] = { 0x12, 0x42, 0x98, 0x85, 0x49, 0x3A }; //MAC address of server 
char server[] = "http://52.1.29.117/"; //web address of server 
IPAddress ip(172, 31, 51, 13); //IP address of server 

void callback(char* topic, byte* payload, unsigned int length) { 
    // handle message arrived 
} 

EthernetClient ethClient; 
PubSubClient client(server, 80, callback, ethClient); 

void setup() 
{ 
    Serial.begin(9600); 
    while (!Serial) { 
     ; // wait for serial port to connect. Needed for Leonardo only 
    } 

    // start the Ethernet connection: 
    if (Ethernet.begin(mac) == 0) { 
     Serial.println("Failed to configure Ethernet using DHCP"); 
     Ethernet.begin(mac, ip); 
    } 
    delay(1000); 
    Serial.println("connecting..."); 

    if (ethClient.connect(server, 80)) { 
     Serial.println("connected"); 
     // Make a HTTP request: 
     ethClient.println("GET /search?q=arduino HTTP/1.1"); 
     ethClient.println("Host: www.google.com"); 
     ethClient.println("Connection: close"); 
     ethClient.println(); 
    } 
    else { 
     Serial.println("connection failed"); 
    } 

    // if (client.connect(server)) { 
    if (client.connect(server, "ubuntu", "")) { 
     Serial.print("Data sent/n"); 
     client.publish("hello/world","hello world"); 
     client.subscribe("hiWorld"); 
    } 
    else { 
     Serial.print("nope"); 
    } 
} 

void loop() 
{ 
    client.loop(); 
} 

Answer 1

IIRC AWS只打開了幾個特定的​​端口，這可能會幫助你打開一些：

http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/authorizing-access-to-an-instance.html