I don't know if anybody have issued this, but I wan't to ask. My problem was like this:
I could use video chatting from apprtc.appspot.com using two Chrome tab (which means I call myself). Everything worked well.
I could use apprtc with two different laptop as well, if those laptop were on the same network. I used my university's network behind proxy.
However, apprtc didn't work if I used it with one laptop on modem, and the other on LAN.
Can anybody explain what happened? Is this STUN/ICE problem? Or JSEP?
The public demo includes a STUN server but does not provide a TURN sever because the bandwidth to run a free TURN server is expensive. STUN get thought lots but not all NATs / firewalls but not anywhere near as many as TURN. You might be in a situation where TURN would work (but you don't have a TURN server) but STUN does not.
I've been able to use the demo at http://apprtc.appspot.com/ from behind two different NAT's. So it can at least work in theory; but it's also fairly well known that STUN, TURN and ICE aren't infallible. For starters, if someone has blocked access to the port 19302 (the port of the STUN server that the apprtc demo uses), the firewall traversal will never be able to get started.
The basic troubleshooting step would be to open up the Chrome developer tools (ctrl-shift-i) and look to see if there are any errors in the console. Failing to observe anything interesting there, you'd need to write up your own version of the demo app, this time with better error handling. For instance, the apprtc demo assumes certain things that can't really be taken for granted, for instance, that peerConnection.setLocalDescripton() and peerConnection.setRemoteDescription() will succeed. In production code, you'd really need to implement both success and failure callbacks on those - and that would give you better information about what might be going wrong.
AppRTC uses stun by default. TURN is 'better' (from my understanding), but I recall Justin Uberti saying public TURN servers will likely be misused (or something to that effect).
STUN often fails on enterprise grade subnets because it can't 'cope' with unfriendly NAT addressing.
Related
I was going through this PubNub WebRTC demo. https://kevingleason.me/SimpleRTC/minivid.html
Which works fine within same network (same browser or different devices across same network). But I tried using it over internet, I am able to connect a call but can not see anything but a black screen. This is the source for same tutorial
https://github.com/pubnub/SimpleRTC
I have gone through many such application, such as AndroidRTC
and I face same problem (black screen after connection over internet). I am unable to figure out why, any help is appreciated.
You need some sort of signaling mechanism (PubNub, Firebase, or your own software [nodejs seems the preferred choice these days]) to get the webRTC API communicating P2P on your local network. To get webRTC to work from one network to another you need a STUN server/service. Google provides free stun servers (stun:stun.l.google.com:19302). To get webRTC to traverse strict firewall settings and complicated networks you need a TURN server/service like xirsys.com.
This article covers it all ...
http://www.html5rocks.com/en/tutorials/webrtc/infrastructure/
I am doing a multiplayer game using UDP protocol (DatagramSocket and DatagramPacket). The program has to do client and server at the same time. This works fine on LAN networks, but I would like to make it work on Internet too. I have tried to use hamachi, but it doesn't work, the information goes only in one direction.
EDIT: Ok, I ask in another way. Is there any java class, program or anything else to connect two computers on internet using java?
Ok, I have just resolved the problem. It works fine with hamachi. I was copying wrong IP's, so it didn't work. If you exchange your IP's to each other, It works.
I writing a mac application and i need to discover other Macs/PCs/iPhones/iPads connected to the same WIFI network.
Bonjour seems to be the most reasonable choice, but it turned out that it has problems on many types of routers (on mine for example, is not working as it blocks Bonjour services).
I just need to find iPs of devices, then i will try to connect to an application-specific port to determine if my process is running there.
What is the best approach to accomplish this task, without violating the App store Sandboxing?
ARP was the first answer which came to my mind. Does your network-setup allows this?
I'm currently developing a simple multiplayer game app for Android and I need to have a server to which the users connect to.I'd like to set up this server at home. I have a dynamic IP address,so someone told me I'd have to set up a local DNS server or something like that. I'm not even sure where to start with setting up a DNS server, everything I found was for windows 2003 and linux. Nothing for XP? If any one can shed some light on this matter, explain a bit how setting a DNS works or supply a link with "setting up local DNS for dummies" I'd be grateful.
Also, besides setting up a DNS so I can find the server every time, how about the communication with it? I'd like for it to be as secure as possible. Another friend told me something about communicating via SSH, which is again something I am not accustomed to.
So if someone could explain some of these concepts or offer some GOOD link for that that would be great. I'm very confused :)
Thanks
EDIT
Btw, the server is in Java and currently i'm communicating from Android emulator to the server (which is localhost) via sockets.
That's not a simple thing you're trying to achive. First you have to create your own server on your machine (maybe you're done with this step), then you have to make this server available for everyone. At this point, I suggest the DynDNS service:
http://lifehacker.com/124804/geek-to-live--how-to-assign-a-domain-name-to-your-home-web-server
A local DNS by default help you to find your own servers by name instead of IP address, but if you have a usual internet service with dynamic IP, you need an external DNS provider to route your clients to your server. (read the link above for the full explanation)
About the SSH security: Yes, you will need some security settings indeed, but that could be a very hard problem sometimes. You can set your server to work with SSL sockets, which is a part of the core J2SE release. It will work against some sort of attack, but none against others. Running your own server will raise unexpected numbers of problems, prepare for that.
As already stated in the comment to your post, something like http://www.no-ip.com or http://www.dnsdynamic.org would solve the issue with your dynamic ip - You do not need a local DNS server.
With regards to communication, i believe that SSH is linux/unix only. Since you wish to use Windows for the server, FTP or Remote Desktop would be best. Choose FTP if all you want to do is manage your files, choose remote desktop if you wish to manage your entire computer. I've had good results with the FileZilla FTP server on windows (http://filezilla-project.org/)
With that said, i think you would be better off buying a simple and cheap hosted service instead of using your own computer - you can get something that can run your java app for $5/month some places, and compared with the annoyance of having a local server running in your house, it might be worth it.
Simplified, I have an application where data is intended to flow over the internet between two servers. Ideally, I'd like to test at what point the software ceases to function. At what lowerbound limit (bandwidth, latency, dropped packets) do things stop working to test the reliability of the software.
What I thought I would do was the following:
Setup up 3 machines (VMware instances)
Install the 2 applications on two of the servers.
Setup up the 3rd server to sit between the two machines by doing some sort of magic with Routing and Remote Access on Windows 2003
Install either Traffic Shaper XP or NetLimiter to limit the bandwidth
Run something like TMnetSim Network Simulator to simulate a bad connection.
Does this sound like a good idea or are there easier/better ways of doing this? I'm not that comfortable on Linux and my team mates are even less so.
WANem does exactly this. We have used it both in a virtual machine on the desktop and on a dedicated old pc and it worked great. It can simulate all sorts of broken connectivity.
FreeBSDs ipfw has provisions to simulate links with a given bandwith, latency or error rate. You could use that FreeBSD machine as your machine "in the middle" in your above setup.
You probably can also run at least one of the endpoints on the same machine if you want to reduce the amount of servers involved.
Someone actually packaged up the settings and whatnot necessary for the FreeBSD solution to this problem and they call it DUMMYNET.
It simulates/enforces queue and bandwidth limitations, delays, packet losses, and multipath effects. It also implements a variant of Weighted Fair Queueing called WF2Q+. It can be used on user's workstations, or on FreeBSD machines acting as routers or bridges.
It can simulate exactly what you want, and its free and will boot onto commodity hardware. They even have a canned install of it that is small enough to put on a floppy disk (!) that you can download at that link.
Maybe it is time to learn a bit about Linux because adding a 50ms delay on every outgoing packet can be done in typing just one line:
tc qdisc add dev eth0 root netem delay 50ms
For more see the Linux Traffic Control HOWTO
We had a similar requirement some ten years ago - I'll see if I can recall how we managed it.
If I remember, we wrote a socket proxy program which was controlled by inetd on a UNIX box. This socket would accept connections from a client and open equivalent sessions through to the server. It would then loop, passing messages in both directions.
The way we achieved WAN characteristics was to introduce random delays (with upper and lower limits) in both the connection establishment and the passing of data once the link was up.
It also had the feature to drop the link occasionally as WAN links were less reliable for us than local traffic.
I recall we had to make it threaded to stop the delays from affecting reverse traffic on the link.
There is a very good (and free) Microsoft solution for that, we use it for quite some time and it works great, it can very easily simulate every thing(packet loss, low bandwidth, disconnection, latency....)
This is the best solution i found for a windows environment
More information and a download link can be found here: MARCO blog post
this product has gone some evolution and it is now integrated into visual studio as part of the automation testing, but i found the use of the standalone(that is quite hard to find, so keep a local copy) to work much better. keep in mind that you need at least two computers(or VMs) since you need to pass through a network adapter in order for the application to work its magic.