I'm new to network programming. I want to traverse NAT using Stun. I use the Stun client application defined in code project Stun Client. It returned me a mapped IP and port. But I don't know how to use the IP and port for P2P communication in C#.NET.
Please help me. Any help will be appreciated.
If you're looking for some general background to get you started, look at this related question:
.NET and P2P - writing a P2P messenger
HI all
we found that, we can traverse NAT using vs2010 (.net4.0) . there is a method AllowNATTraversal(bool value). set the value true for NAT Traverse. It uses Ipv6 adsdress for connectivity. You can get Ipv6 global address from teredo server by writing some comands in command prompt.
Related
Excuse me. I speak poor English.
I am trying to create a network proxy programming with sock5 protocol. But I have no way to learn it, I can't figure out how a proxy programming works especially the followings:
What is the difference and association between socks5 and the Shadowsocks ?
Can I set a the network proxy configure in macOs instead of using swift or oc ?
such as enabling this check button(socks5 proxy) and filling the specific configure using a language instead of swift or oc:
configure
Once I set the option on macOs in the Question 2,what kind of data will the programming get if it listening the network?
e.g. will the macOs automatically forward the all new TCP connections to 127.0.0.1:1086 and automatically make the connections confirm to the socks5 request standard?
If so, why the final processing programming (transmit the datas to the real remote proxy-server) can make a successful connection? Instead of a forever loop(a.programming create a socket to remote proxy-server -> b. macOs automatically forward it to 127.0.0.1:1086 and make the connection confirm to the socks5 request standard -> a.)
Is it called as a proxy-client? or local proxy-server? what is the job of it. Why do I set a proxy address as a local one instead of a direct remote server?
Why when I setting a fake socks5 option in macOs network proxy options, a UDP programming can still work successfully?
If you can UNDERSTAND CHINESE:
Chinese language
The follow answers are based on my own experience and opinion.
1、socks5 is an Internet protocol that exchanges network packets between a client and server through a proxy server. Sockes
while Shadowsocks is a software use this protocol.
2 、Yes,you can. Install a Shaowsocks don't need any
Programming language, actually it like installing a EXE file on Windows or pkg on MacOS, it's just a software.
3、Socks5 is an Internet protocol like a language between two computer.
The software's message run on you computer will be "translated" by Shadowsocks.
Those translated message will be sent to the remote service (also run a Shadowsocks) then the service can send message to those "blocked" Webs' services.
4、The remote service can be called an proxy service.The local don't do anything except be "translated" by Shadowsocks. Look this picture.
5、The QQ don't use the port 1080, Shadowsocks need a fixed port to "translate" message.
I need to write my first socket program involving TCP connections. In the program I have created there is a client and server, both of which are the machine I am coding on.However,it requires that I pass the port number as a command line argument. How do I accomplish this?
The answer is simple : Make sure your server and your client agree on the port to use. As long as the port is available and can be used, set up the connected so that the client and server use that same port.
Here's a link that explain the different ranges available for TCP and UDP ports.
As an exemple, the port 3074 is used by microsoft for its Xbox live service. Making an application using this port might interfere with the service.
The port used will be defined either in a configuration file or hard-coded in the source code of both the server and the client. You should easily be able to find it with a quick look at the code or the directory which contains the application.
I need to connect to a remote server via a modem for a legacy app. I don’t have physical access to my server so adding a real modem isn't an option.
Does anyone know of:
A service that provides Modem Over IP? Something like Twilio, but just for modems.
A modem / SIP client that would allow me to emulate a modem on a specific COM port that connects to a VOIP provider?
Any advice would be greatly appreciated. I see quite a few people with this problem, but no great solutions.
Thanks!
Steve
I think what you are looking for is PPP (or maybe PPPoE). PPP is very common and is still used heavily today pretty much everywhere you have a home connected internet connection.
You need to look at whatever OS you are using and see what they provide to be able connect two computers via a modem and create a TCP/IP connection between them. That way you don't need to change your program, as it will showup as a network connection.
Under windows you have this for accepting incoming connections.
I am working with the BlueZ libraries for managing the bluetooth stack under linux. I am trying to open a socket that should connect with a specific service whose UUID is known. I have successfully tried to open sockets between a server and a client following the examples here:
http://people.csail.mit.edu/albert/bluez-intro/c404.html
where it is also described how to explore services in a remote host; however, what I cannot figure out is how to specify the UUID while connecting the socket. This is something quite straightforward on other contexts, as it happens when using Android libraries; however, with BlueZ I haven't found examples on the web.
Thanks for the help!
Stefano
-- added some details in a reply... don't know if it's right or not; if not, sorry
thanks for your help!
In my post I said I wanted to connect a socket with a specified UUID since I had in mind a function like createRfcommSocketToServiceRecord as can be found in:
http://developer.android.com/reference/android/bluetooth/BluetoothDevice.html#createRfcommSocketToServiceRecord%28java.util.UUID%29
which returns a socket given a certain UUID. I am developing two softwares, one being the client and the other the server, therefore it's a service I am creating, not a standard one. I publish such service on the server with a specified UUID, and I would like to connect to it from the client. The server is running fine, since with an android platform, exploiting the mentioned createRfcommSocketToServiceRecord method, I am able to connect to the server with the right service.
The example you posted is very clear as well, but unfortunately it is in Python, while (I forgot to point out) I am using Bluez as a C library. I am able to exploit the SDP and inspect services on a remote server; however, when it is the time of setting up the socket, I don't see how to specify the port. I thought about the rc_channel, but as far as I understood it is the bluetooth channel (ranging from 1 to 11 or something similar). Could you please point out Where I should be able to specify the port while creating the socket in the client? And where am I able to find the right port in the complex structure the sdp is dealing with? -- referred to:
http://people.csail.mit.edu/albert/bluez-intro/x604.html
Thanks again for the help!
You don't connect sockets by UUID. You use a socket to connect to remote device and browse its SDP to discover the UUIDs it offers, and map that to a socket port. Here's an example of this process using PyBluez, python wrappers above BlueZ
http://people.csail.mit.edu/albert/bluez-intro/x290.html
Hey I'm trying to get a CFStream connection going over 3G. I can get it working over wifi using the host name, but when I try to connect directly to the ip address it fails.
Is there a guide out there on how to connect over 3G?
Thanks
ASH
You can use NAT traversal in some cases. This is not a guaranteed method and depends on the type of NAT so you will still need a relay server if you want to guarantee connectivity.
A general rule is if both clients are behind symmetric NATs then a relay server is required.
If only one NAT is symmetric then STUN, ICE, methods can be helpful in establishing P2P connections.
The following might help you:
Interactive Connectivity Establishment see en.wikipedia.org/wiki/Interactive_Connectivity_Establishment
PJNATH Open source project for NAT traversal in SIP/VoIP solutions see PJSIP.ORG
When you are connected to 3G then you are usually behind a router that implements some 'NAT' scheme. This means that your iPhone gets a private internal IP address on the inside (the 3G network) and a shared 'real' public IP address on the outside (the Internet).
This is all fine when you are just a client connecting to services on the Internet, but it will fail horribly when you try to connect to other clients in the same situation.
There is no simple solution for this. Programs like Skype work around this problem by using intermediate servers with public IP addresses that can relay network traffic between hosts behind such 'NATted' networks.