MQTT doesn't like static IP address

Projects Networking, Protocols, and Devices
1

It would seem problems are going to keep happening to me.

I have got the PING issue resolved.

Moving on from that, with the NodeMCU arduino and the next problem arises.

As it was originally - and only for testing - I used DHCP.
Now I am wanting to move on to FIXED IP addresses so it is easier to find/see machines/states.

The other quirk is that I am using MQTT as well. I say quirk only because something is happening that I don't understand HOW it is happening.

Status quo, the sketch works. The Arduino/ModeMCU connects to my WAP.
It gets an IP and it talks to my MQTT quite happily. Sending the dummy test messages which for now are ok.

But when I make it a STATIC IP address, the MQTT fails.

This is the wifi-setup part of the code.

void setup_wifi() 
{

  delay(10);
  // We start by connecting to a WiFi network
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.mode(WIFI_STA);

  WiFi.begin(ssid, password);

//   With these lines as they are:  It works.
//   If I make them active and set the IP address, MQTT won't talk.
//  IPAddress ip(192,168,1,2);   
//  IPAddress gateway(192,168,1,1);   
//  IPAddress subnet(255,255,255,240);   
//  WiFi.config(ip, gateway, subnet);


  while (WiFi.status() != WL_CONNECTED) 
  {
    delay(500);
    Serial.print(".");
  }

  Serial.println("=================");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
  Serial.println("=================");
  connected();
}

I've added comments in the code, but here is the story:
The network is 192.168.1.x/28
The WAP is .1, I want the Arduino thingy to be .2 and the broadcast address is .15

With the lines active this is what I see in the serial window:

Connecting to PiNet
.=================
WiFi connected
IP address: 
192.168.1.2
=================
Done
Attempting MQTT connection...failed, rc=-2 try again in 5 seconds
Attempting MQTT connection...failed, rc=-2 try again in 5 seconds
Attempting MQTT connection...failed, rc=-2 try again in 5 seconds
Attempting MQTT connection...failed, rc=-2 try again in 5 seconds
Attempting MQTT connection...failed, rc=-2 try again in 5 seconds

But it is being PINGed as .2

How is changing the IP from DHCP to static changing the fact MQTT won't talk?

2

Have you updated the WAP DHCP address range to exclude 192.168.1.2 from the address pool? If not then you may have two devices with the .2 address.

I don't know how configurable your WAP is, but my own setup uses DHCP for everything with static IP/MAC assignments setup in the WAP. This allows you to manage all IP/MAC address combinations in one place rather than having a mix of DHCP and non-DHCP assignments.

3

From the RPI config files:

/etc/network/interfaces:

allow-hotplug wlan0
iface wlan0 inet static
  address 192.168.1.1
  netmask 255.255.255.240
##  14 usable addresses.  (Well 13, as this is one of them)
#  network 192.168.1.0
  network 192.168.0.0

/etc/dhcpcd.conf

interface eth0
inform 192.168.0.99/24
static routers=192.168.0.254/24
static domain_name_servers=192.168.0.254/24
static domain_search=192.168.0.254/24

static routers=192.168.0.254

denyinterfaces wlan0

/etc/hostpad/hostapd.conf

cat hostapd/hostapd.conf 
interface=wlan0
driver=nl80211
ssid=PiNet
hw_mode=g
channel=7
wmm_enabled=0
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_passphrase=************
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP

The wpa_supplicant file is nothing special.

This is getting a bit more "Ras Pi" than Arduino.

But that is what is on the RPI.

I have (from the other thread) a ping test and when I connect the Arduino, it only connects one IP address.
via DHCP it is 7. Via static it is 2.
via DHCP the MQTT works. I get messages coming through and I can send messages to the board. All good.
via static, it pings. But MQTT just won't have a bar of it.

Anything else needed?

4

Just found this which I think is contributing to the problem:

WiFi config()

And it shows this bit of code:

#include <SPI.h>
#include <WiFi.h>

// the IP address for the shield:
IPAddress ip(192, 168, 0, 177);    

char ssid[] = "yourNetwork";    // your network SSID (name)
char pass[] = "secretPassword"; // your network password (use for WPA, or use as key for WEP)

int status = WL_IDLE_STATUS;

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

  // check for the presence of the shield:
  if (WiFi.status() == WL_NO_SHIELD) {
    Serial.println("WiFi shield not present");
    while(true);  // don't continue
  }

  WiFi.config(ip);

  // attempt to connect to Wifi network:
  while ( status != WL_CONNECTED) {
    Serial.print("Attempting to connect to SSID: ");
    Serial.println(ssid);
    // Connect to WPA/WPA2 network. Change this line if using open or WEP network:    
    status = WiFi.begin(ssid, pass);

    // wait 10 seconds for connection:
    delay(10000);
  }

  // print your WiFi shield's IP address:
  Serial.print("IP Address: ");
  Serial.println(WiFi.localIP());
}

void loop () {}

How ever, if I try to do that I get an error:

 WiFi.begin(ssid, password);

  // the IP address for the shield:
  IPAddress ip(192, 168, 1, 2);    


  WiFi.config(ip);

               ^
exit status 1
no matching function for call to 'ESP8266WiFiClass::config(IPAddress&)'

Anyone?

5 
allow-hotplug wlan0
iface wlan0 inet static
  address 192.168.1.1
  netmask 255.255.255.240
##  14 usable addresses.  (Well 13, as this is one of them)
#  network 192.168.1.0
  network 192.168.0.0

The network value is definitely wrong. The commented out value is the right one.
I don't know how the Raspberry Pi interprets these conflicting values but you might have a misconfigured network interface, so the Arduino probably cannot reach the Raspi.