I have 2 nodeMCU modules, which I want to connect to an MQTT broker and send some data every 5 seconds.
The topology I am trying to achieve is sth like [router]<==[nodeMCU#1]<==[nodeMCU#2]
It looks like [nodeMCU#1] is a wifi extender, but at work we are planning on using multiple nodeMCU's to use in a mesh-like way for an IoT application.
On both of them I flashed the latest (float) release that I downloaded from here https://github.com/nodemcu/nodemcu-firmware/releases/tag/0.9.6-dev_20150704 using nodeMCU-flasher.
For this project wrote 2 lua scripts and I have uploaded them to the modules using ESPlorer.
For the first module it connects in STATIONAP mode to my work wifi, and creates its own network with SSID nodeMCUwifi, with a basic password of 10 characters "1234567890". After it connects the script sends random values to an MQTT topic.
For the second module connects to nodeMCUwifi correctly, it is assigned an IP address, but it cannot connect to the MQTT broker.
When I try to connect to nodeMCUwifi using my smartphone (just to test the connection, I have no intention of using this system for heavy internet load, only MQTT messages) I get a message "authentication error occured" even though I have typed the password correctly, or (in rarer cases)it connects but disconnects immediately.
I would appreciate any ideas to resolve this issue. Thank you.
EDIT: At the AP configuration I added the auth parameter set to 3, I am pasting a part of my code below.
cfg.ssid="ESP8266_"..node.chipid();
cfg.pwd="1234567890"
cfg.auth=3
wifi.ap.config(cfg);
Now my laptop and my smartphone connect to the wifi created by the module, but still have no connectivity to the internet. I can ping the module, but I can't ping 8.8.8.8 or the MQTT broker IP or anything else.
As I understand, [nodeMCU#1] creates a wifi network named nodeMCUwifi. Then the others are trying to connect to nodeMCUwifi. As You stated:
Now my laptop and my smartphone connect to the wifi created by the module, but still have no connectivity to the internet. I can ping the module, but I can't ping 8.8.8.8 or the MQTT broker IP or anything else.
I assume your laptop and smartphone connects to the nodeMCUwifi network. Now you want this [nodeMCU#1] act like layer 2 switch or something like router(since SOFTAP creates its own ip network).
With all this information on hand, I can say that the purpose you are trying to achieve is not possible with esp. Since esp has not enough resources to act like switch or similar. Also (currently) there is no software implemented in esp to achieve that.
However; if only you want the system to transfer certain type of traffic (such as MQTT) over a certain protocol (such as UDP) it is possible to relay the messages like a mesh structure but this will work one-way only. In this configuration the nodes will act more like repeater but on upper layers of OSI. For this idea i cannot provide sample code but I will provide pseudo-code below:
Configuration
> Each node must be configured to build a chain structure. That means each SOFTAP node should have different SSID or TCP settings. For example:
router(192.168.0.0)<----[NODE#1(SOFTAP0)]<----[NODE#2(SOFTAP1)]<---...
...
...
...<----[NODE#n(STATION)]
> Each node must have a TARGET IP address according to setup. This means every node will send the MQTT message to that address.
> If a node is configured as a SOFTAP, this means this system is a TARGET and must listen to a specific port.
> If a SOFTAP node receives some data on the port that is listening to, it should send the data immediately (or buffering) to its TARGET node.
> As a result of this chaining operation the message, no matter what is the source, will reach to the end of the chain.
CODE : SOFTAP
...soft ap config...
listento.port: udp.965
on("receive"):
create.conn:TARGET
send(DATA_RECEIVED)
close.conn:TARGET
CODE : STATION
...station config...
...Do some logic...
data=gather.data()
create.conn:TARGET
send(data)
close.conn:TARGET
Related
I have a language monitor that I am trying to query the printer from.
First let me apologize for the possible confusion since "port" means 2 things in this description. There is the one use that refers to the port that the printer is configured to use, which could be TCP, USB, etc. And then there is the use of port that refers to the port address to send data to when communicating with the printer's IP address.
I need to be able to specify different port addresses to send different custom queries to a printer over the same IP that are specific to it's firmware. I can't find any examples or documentation on what the standard way is to do this communication... I can extract the IP address and open a net socket, but I am not sure if this is the appropriate way to handle this communication. It's not uncommon for printers to send status over one port, and print data over another. If i want to write to the Default port I can use pfnWritePort and pfnReadPort, but these don't allow me to specify the actual port.. it uses whatever the driver is configured as.
Can anyone provide some guidance or examples of how I should do this from my language monitor?
EDIT: As an example for clarification, all commands are sent to the same IP, but depending on the command/query I need to send, the TCP port needs to change. The way I am handling it now is opening up a net socket with the same IP and different port numbers for data and status channels).
You should be required to write an app that would be able to reconfigure driver. Ideology of OS is that EACH real device would corresponds to instance of driver and\or interface. Which might be an elevated action, because it requires to create new printer interface("port" in Windows GUI terms) and change driver settings.
I want to send small (a few bytes) data from one ESP8266 to another over long distances.
I believe the signal is too weak to connect one ESP8266 to another but maybe they can receive small messages with some delay?
How can I achieve that using arduino-esp8266 library (or whatever)?
If ESP8266 boards can not connect directly to each other because of the weak signal (approximately more than 50m between them) you can still connect them to each other (indirectly) if they are connected to the same WiFi network created by external router or internet. But you can connect them to each other without need to connect to any external network only if they are in range of each other.
It both of them are connected to same local WiFi network router you can communicate between them as if they are connected directly to each other. Just in this case router option "WiFi Client isolation" must be disabled in router settings page for boards to see each other(in case that router has this or similar named option).
Otherwise if ESP boards are connected to totally different networks, but both of these networks have access to internet, you can still connect them to each other but then you must use port forwarding on each router, so both of the ESP8266 boards are visible form internet. Google a bit about it, it is not so complicated. In this case you can have boards on any two locations in the world and make them communicate to each other as long as they are accessible from internet.
Maybe it is hard to test it when your code do not work out of the box, so I would recommend that you use some TCP or UDP terminal to test connectivity between two WiFi clients on different or same network. There are buch of such terminals available online.
For example for sending and receiving UDP packets same way as you would send/receive data from serial port, I use Docklight Scripting.
https://docklight.de/downloads/
I actually use it also for other Serial port communication so no big difference there. Don't let description text on their page fool you. It can also send/receive TCP/UDP data :)
Just when you create new project go to tools->project settings and type IP and port of another device you want to connect with (this can be another PC running docklight scripting or your ESP board). For example in my case I type in
Send/Receive Comm.: UDP:192.168.0.154:9761
Because that is the IP of my ESP board on local WiFi network and press "play button"or F5. Now you can send receive data to your board using UDP in same way that you communicate to basic serial port and in such way test basic connectivity. Or even use two laptops just to confirm connectivity between two WiFi clients on network.
And third hardest option must most versatile is needed if you do not have access to routers setup page (they are password protected) and cannot set port forwarding, then you must create server application on some server that is visible from internet and has public IP. So both of your ESP8266 boards are connected to this server as clients (for client port forwarding do not need to be set but in this case you must have access to internet by both clients) and server can forward their messages to each other. But this is way out of this topics scope. Maybe for start you use TCP/UDP terminal just to check connectivity between two WiFi clients and see if ESP8266 can communicate directly or not. Docklight scripting is just suggestion because it is my personal choice for TCP/UDP/RS232/RS485/MODBUS/USB HID, but you can use other software for this.
I hope this helps a bit about ways to connect two ESP8266 boards indirectly.
When creating a peer to peer audio connection using webRTC, the STUN server we use will return the public IP if a user is behind a router. Now in the ICE objects, I can see that the rport is always something between 50000 and up.
Is there a way to use a specific port so that the user does not have to open all those ports?
Is there a way to use a specific port so that the user does not have to open all those ports?
I think you have a misunderstanding. The whole point of STUN and ICE (including its WebRTC derivative) exists to avoid anyone having to open a port on their NAT. Instead, STUN and ICE dynamically open the port.
Here's how it works (in a really brief description).
Client opens a socket on a random port (e.g. 50001)
Contacts STUN server using that socket to discover the external IP:port mapping for this socket. (e.g. 192.168.1.2:50001 maps to 1.2.3.4:50001). Ports don't necessarily have to match between internal and external addresses, but they usually do, so I'll keep with that for this example.
Through an external mechanism (SIP, XMPP, Jingle, cups with strings), the candidate address list of both nodes are exchanged. This includes all known internal and external addresses collected (e.g. 192.168.1.2:50001 and 1.2.3.4:50001).
Using the same socket opened in step 1, both sides send (STUN) messages (UDP packets) directly between each other. The first pair of messages may be blocked by the router/firewall. But because one side initiated an outbound packet to the remote address, subsequent packets from that address are allowed back in. This is called the "hole punching step". Hence, the port is dynamically open without the router needing any specific configuration.
Hope this helps.
You can't programatically unless you are using webrtc API in your own application. The browser will pick specific local ports from a range locally; and then it will inform you about them in the SDP and ICE candidate information.
STUN server only helps discover whether a client is behind a NAT/firewall; and then ICE uses this information in establishing peer-to-peer connection.
I have heard somewhere there might be a way to control that port range via Chrome policy templates(used by enterprises to restrict Chrome settings) - http://www.chromium.org/administrators/policy-templates. It might worth looking into...
I've set up a networking project to communicate over LAN or WAN via hole punching. I'm using GCSAsyncUdpSocket for the clients. I have a rendezvous server which is port forwarded to be accessible from all incoming connections. My setup works like this:
Client A connects to the server.
Client B connects to the server.
Server observes the IP address and Port used by both clients.
Server tells Client A to communicate with public IP Address B and public Port B.
Server tells Client B to communicate with public IP Address A and public Port A.
Client A sends periodic data to Client B.
Client B sends periodic data to Client A.
This is where it goes a bit weird. While the clients are on the same network, which we've tried on both our networks, nothing works. But, if the devices are connected on different networks (both with different providers and are not linked directly) then one of the devices receive data, while the other does not.
This also fails to work on 3G completely.
What I can't understand is how it works 1-way with 1 device on each network, but not at all with both devices on the same network?
I've since found that one of our routers is detecting the messages being sent from one client to another contain different target IP addresses of that to the Server, and then our router decides that these messages should then be sent via a different external port. This is where the problem was coming from. Using a bit of port prediction, this hurdle can be overcome most of the time.
For those who are interested, most of the time if a connection cannot be found at the presumed port, it will most likely be at the very next port (ie. Port# + 1). If not, it gets a little bit complex from there to work out.
I would like to setup a network connection (RTP or UDP) between two computers at different locations, each of which is behind a NAT modem/firewall. I do not want any modification of the firewalls.
My working assumption is that I need a bot somewhere that both computers can reach (eg a shell account on an internet server). Each computer connects out to the bot and the bot allows the two computers to update and query status and to exchange data.
This is ok as far as it goes, but it means that all data travels via the bot. Is there a way I can connect the two computers without the bot, or failing that, allow the bot to drop out of the data exchange once a connection has been setup? My feeling is that there is no way to do this, but my TCP/IP is a bit rusty...
If you assume nothing on the NAT/Firewall your are correct.
Hole-Punching for example will not work with overloaded NAT (PAT) as far as I know, because the source port is randomized by the NAT device, and it maps/match both the destination public address and the picked up source port elected.
UPnP may work, but again you need to assume it exist and enabled on the NAT device.
As I see it, you got only two options if you want to be generic:
1. Configure the NAT.
2. Use a proxy (the bot you mentioned).
Skype for example uses the second, but does it in a distributed manner by using every Skype client as a potential proxy (probably only if it detects it is not behind a NAT or not limited by it).