I have a machine that boots (simultaneously) VxWork and Windows 10 IoT.
The hypervisor sets up two virtual Ethernet adapters. I can see that both exist.
The VxWorks VM is sending out UDP packets to the address that the Windows VM has, and there is a service on Windows listening for the packets on the correct port.
If I run Wireshark I can see the packets from VxWorks and they are being sent to the correct place, but the Windows service isn't picking them up.
The Windows service picks up packets if I run a python script to simulate the data to be sent and tell the service to listen to localhost.
What could be going wrong?
It turns out I need to configure the Windows Firewall. I have turned it off for now and the connection is being established.
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Hi I created a program let's say using ABAP and I want to monitor the data sent to my serial port (COM port)
Now there are a lot of software out there that can help me monitor this transaction.
But the problem is that the software only built to monitor data send from outside the computer.
For example some device sending data through com port to your pc.
BUT when you send the data from your PC to serial port it will raise an error on PORT is already open.
The way the port monitor software works is first opening the port and the read the data send to the serial port.
The problem happens when my own custom program try to send data to serial port, where I also need to open the port first.
So in order for my program to work then I have to shutdown the serial monitor software (this way I cannot use the monitor program).
But If I turn on the monitor software, then it will open a port that will make my program to become error and cannot open a port (I cannot send any data to serial port).
If I send data using my program without opening a port then it will send nothing.
You need to use com port emulator software. Generally these programs create virtual comport for listening. You application must connect to this virtual port.
Some of these emulator programs can connect virtual port to the real port. So you can get inbound and outbound data.
I have successfully compiled source code of doubango opentelepresence system (An open source video conference MCU) and successfully tested. I can make video calls through desktop version and using webrtc (sipml5 client) with Chrome and Firefox (with some modifications because the sipml5 was not compatible with newer versions).
Now my problem is with NAT traversal. I want to make video calls between clients behind NAT using turn server. The MCU server is behind NAT (SIP port is on public IP using port forwarding and tcp sip and ws connection is available). I have installed coturn Turn Server on a ubuntu system, and configured it using command line as like why the turn server does not support for the tcp connection. The turn server ports is open on public ip. I have also tested both udp and tcp but not successful.
On the mcu, ice, stun and turn is enabled. I have set turn server url and credentials correctly and the mcu can successfully communicate with turn server. Also webrtc on the browsers can successfully communicate with turn server (I say successful communication, because I can see candidates are being generated).
I have two major problems:
For some reasons related to firewall, I prefer to use only tcp relay. But in test environment, I have tested both with udp and tcp but not successful. It seems doubango opentelepresence does not support relayed tcp, because I cannot see any candidate with relayed tcp (there are udp relayed candidates).
What is wrong with my configuration which I was never successful on making a call. The ICE candidates are generated with public ip, but their state is always failed or frozen (what does frozen mean!). If you have any suggestions, let me know and try. I can test and report results here until reach a successful video call.
Yellow parts are public IP address (a valid IP address accessible on the internet for all clients).
I am connecting my controller PC to a Pica8 white switch via the Management port. I can SSH into the switch and ping the controller PC, however I cant ping the hosts through the standard ports. I have created a bridge of the first four ports and have successfully pinged from host to host after I installed a flow that allowed it.
My question is, is there some kind of mechanism separating the controller port from all of the data ports, I would think I should be able to ping from the switch to the hosts.
I'm not sure this answers your question, but before pinging the management port I believe you need to set an IP for it via the console port.
I use minicom per the instructions located here. However, I am using the RJ45 to DB9 adapter cable -> USB Serial port connection. That looks like so.
Unfortunately, that creates a problem with minicom, since the instructions tell you to simply power up the switch and observe the received data. There is actually a little more to it than that. You have to configure minicom's serial port. Fortunately, there is a tech blog that I found very helpful. If you follow the provided instructions, it will walk you through changing ports. Once you modify the port that minicom is listening on (For me it is Port /dev/ttyUSB0), you should be able to configure your management port.
The underlying problem is I can't upload a file via ftp from a windows 8 laptop to a windows server through my linux/iptables firewall (passive or active ftp, doesn't matter). Works with windows 7, linux, and when I remove the firewall.
I logged all of the packets to and from the server and the same pattern shows up every time it fails. Everything looks normal until I see an RST packet from the server to my laptop. It's from and to ports that have previously been set up and used. The packet is forwarded to the laptop. So far it looks fine. Then the server sends an ACK FIN packet using the same source and destination ports as in the RST packet. This is not forwarded to the laptop and I assume this is because the RST caused the nat table to drop that connection. Is this what should happen? If not, could someone explain how I should set up my firewall? Or is there something wrong between the windows machines?
I use the modules nf_conntrack_ftp and nf_nat_ftp to handle ftp & nat in my firewall.
Thanks!
Could someone please help me to configure UDP in web server to accept connection from GPRS mobile device. The GPRS mobile device will send data packets which i need to write as a file in web server to process a web page. Please help.
i need to know the following:
1) How to configure UDP in web server
2) How can a GPRS mobile device get connected to the server using UDP
3) Write the data packets to a txt file
Please help.
A "web server" usually means am "http-server", which is a process listening for incoming "http"-requests.
Now http is a protocol that is standardized to be accessed via TCP/IP port 80.
Therefore most webserver implementations will implement a TCP/IP server that listens to port 80 by default. Usually you can change the port if need be, but usually you cannot change the transport layer to e.g. UDP.
Therefore it might not really be possible to make your "web-server" react on UDP packets.
If, however, by "web server" you mean a host accesible on the internet (that eventually might happen to run an http-daemon), you might have more luck: simply run a small server-application on that machine that listens to incoming UDP traffic on a given port, and do "something" with it (e.g. forward it to an http-daemon to display the current location)
Answers to your 3 questions:
Creating a small application listening on UDP-traffic:
a trivial server could be:
`netcat -l -u -p 8888`
This will create a UDP-server listening on port 8888, using netcat.
Whatever client connects to your server, everything that the client sends to the server will be output via stdout, and you can talk back to the client via stdin.
You shouldn't use netcat in a production environment; but it is a good and simple tool to check whether a connetion can be established and whether the protocol works.
In production, you will probably want to use a "real" UDP-server, e.g. by writing your own in the language of your choice.
How to make your gprs device talk to your server? This is impossible to answer without knowing more about the device, it's OS and the software installed that produces the data and is supposed to send it to the.
netcat -l -u -p 8888 > myfile.txt