I like to connect to a TCP server that run in a machine that is connected to the LAN in my home network. This LAN can be connected to internet via either following methods.
1. Through a router which has a wireless or wired WAN connection
2. Through a router which uses a mobile broadband connection, for example a router that accept a USB modem to connect to internet.
I know in the first case, we can use port forwarding.
In the second case, I believe telcos use PPP protocol and port forwarding does not work.
In addition, even in the first case, if ISP does not give a static IP, then we need to use DNS mapping service to map a fixed URL to the allocated dynamic IP and we need to configure router to go and register the dynamic ip at the start up.
My question is, are there any other better methods that can be used in this situation? I am wondering how chat applications connect to each other? I hope they maintain a TCP connection between two devices, without a central relay server?
I am in the process of developing a peer to peer app,
I am a bit confused by the following scenario:
Lets say my application will use an outgoing port 1863 - which is also used for msn messenger(if this is not the port lets assume it is)
Now, client executes my app and connects to my server at port 1863.
I am a bit confused if this is going to produce any problems.
I know that 2 apps can use same port for outgoing communication. But what happens to the data coming back?
Also, does my client need to open port for my app to run correctly??
I know that 2 apps can use same port for outgoing communication. But
what happens to the data coming back?
That's exactly the problem the source port solves. The peer can always differentiate between 2 connections based on it. When it sends replies, what was the source port now becomes the destination port allowing the original receiver to correctly pass data to the rightful processes.
I'm writing a C# remote control for my media player. It runs on my Android phone.
I have a client app listening for TCP connections on my computer which, one a connection has been established, processes commands (Volume up, volume down, ...). I've tested that part using telnet 127.0.0.1 on my computer, and it works great.
Things are trickier when it comes to connecting from my phone, since it's not on the same network (I don't have Wi-Fi, only wired connections), so I'm not sure how to proceed. Basically I want to connect to a computer that's behind a router.
Should I rather host the TCP server on my phone, and have the PC connect to it? Take IRC as an example: although I'm behind a router, I can connect to servers outside, without port forwarding.
Or if hosting the server on my computer is fine, how do I connect to it?
I don't understand everything to this yet, so feel free to correct me if I got something wrong.
It would be more logical to keep the PC hosting the server, and configure your router to forward connections to your PC. You have two options:
Establish a DMZ: all incoming connections on the router will be forwarded to one PC only. This is easiest when you only have 1 PC on the network that needs to accept connections.
Configure port forwarding: you can instruct the router to forward connections incoming on port X to the IP Y on port Z. This way, multiple PC's can listing for connections (using different ports on the router). It is also a bit more secure.
How to set these up depends on your router, but most routers just accept connections on their port 80 and offer an easy web-interface. If you give your router brand, we can link you to the manual.
Things are trickier when it comes to connecting from my phone, since
it's not on the same network (I don't have Wi-Fi, only wired
connections), so I'm not sure how to proceed. Basically I want to
connect to a computer that's behind a router.
What you want to achieve is possible, but you need to learn about NAT traversal and hole punching.
Most often, devices behind a NAT/Router have a private IP address only valid on the LAN. Remote devices can't guess it. This private address is translated into a public IP address by the NAT when the device wants to communicate with the WAN.
The easy solution is you can give a public IP address to the device behind the NAT. In this case, remote devices on the WAN will easily be able to reach it, because its address is public.
I want to develop an iPhone app with a simple IM feature. I am thinking about setting up an HTTP server on an iPhone. If the iPhone is using wifi and is behind a firewall, how can I make sure that other iPhone clients can connect to it?
It's not the firewall that will disturb the connection as much it is the NAT.
When you are connected through wireless router to connect the internet you are surfing via NAT. it means you dont really have an extenral IP but once you initiate connection the router will map your intenral IP to one of his externatl ports and for certain time window he will pass connections to you if he will get it to the right port.
That being said, there is no actual way of setting a server behind a NAT unless you can configure port forwarding in the router and internal static IP.
Hope i was clear enough, good luck
I do not really think that you need to get an HTPP server up and running on iPhone to make an application that can send and receive messages (IM). The idea of making one iPhone user to directly connect to one another does not seem right to me since the users will need to know IP addresses of one another to do that.
Interconnectivity between different users of the chat can be solved by making your application communicate via a dedicated TCP port. It is generally advisable to choose ports with a number higher than 1024 since those below are generally found on the list of so-called well-known ports and are used for Web (like port 80), FTP (port 21), SSH (22), DNS (53), etc., it will be the responsibility of the user to make sure the port used by your application is open on the firewall. In order to solve this problem you can actually use port 80 for communication if you find that the port you have selected is blocked. You can do this because you know that this port will not be blocked in most cases. Indeed Yahoo Messenger is reported to use this technique when the firewall blocks the port it uses for communication.
The port should be used by your application to connect to the Web-server that will actually store user credentials, perform authentication, message transmission, etc., and the server should reside on capable hardware to be able to support large number of simultaneous connections. I can suggest using either a VPS (like the one provided by Linode) or a cloud (like Amazon EC2, Google Application Engine, Rackspace).
I implemented a web service for an Android application. The web service is running on my local host (192.168.1.2). Using the Android emulator I succeeded to connect to web service. The I tried to connect my Android device using debugging mode to web service but it didn't work. So my question is if it is possible to connect an Android device to this web service that is running on my local host (192.168.1.2) without using a real IP ?
It's much simpler way supported by google!
Connect your phone via usb to computer and enable usb debugging
On your computer open Chrome browser and type exactly this address: chrome://inspect/#devices
Now you can link your computer port to your device port by port forwarding button. On my computer I have service on address localhost:61437 and I just linked it to device's 8081 port. Remeber to check 'Enable port forwarding' checkbox
screen from service on my computer ( localhost:61437 )
screen from my mobile browser with the same service ( localhost:8081). And that's it. Also you use this service address in your application
Did you already solve your problem? I also got a problem like you. These are the steps that I already done:
unplug lan cable or turn off any other internet connection from your pc.
connect your android mobile to your pc using usb.
turn on usb tethering
back to your pc. check your ip. mine is 192.168.42.37
check your webservice app in your pc. let's say http://192.168.42.37/webserviceapp
back to your android mobile. try this url http://192.168.42.37/webserviceapp
Now you can access your webservice app in your pc from your mobile phone.
Well your localhost is 127.0.0.1 (or ::1) and your LAN IP is 192.168.1.2. Each pc/device that are connected under your LAN could reach your webservice on IP 192.168.1.2
Your Android device must be so connected under the same LAN maybe through Wifi connection so it will be able to talk with 192.168.1.2.
If you can't connect your Android device under the same LAN eg you have just a 3g connection you need to play with your router/firewall to redirect all incoming traffic (maybe just the http traffic) from your public ip to you private ip (192.168.1.2)
Hope this help
I'll throw in my process, since nothing on SO worked for me. Here are the steps I took to connect my physical android device to the web service running on my laptop (connected to the phone) on localhost:
Enable USB debugging on your Android device
Run your web service on your machine. My web service runs on localhost, port 3000 in development: http://localhost:3000/api/...
Run ifconfig (Unix), or ipconfig (Windows)
Find your machine's inet address on your LAN interface. Mine is 10.0.0.121 for interface wlan0. Externally, it is 68.43.XX.XXX, which is not the address that you want to use.
Use the LAN IP since you are connecting to your service on LAN, otherwise you might get an econnrefused (connection refused) error due to firewall rules
Build your http URL with that IP address, and the port that your web service is running on. For me, it's http://10.0.0.121:3000/api/...
When you launch your app, you should connections to your local web service in logs, Wireshark, etc, and you should see the desired activity/data in your Android application.
I had the same issues, researched a lot then found out that you have to explicitly make changes in your firewall settings. Your firewall is blocking your code to be accessed from external source. So, all you need to do is, go to firewall settings, add port 80 (in my case since, I am using Apache http Server) for inbound and outbound. Now, you can test it on your phone's browser http://192.16..**:80/
I've done that on a Mac using GasMask and Charles Proxy Server. Your phone and your computer have to be on the same network.
say the webservice url you want to access is at http://api.xyz.com, you first use GasMask to point that url to your localhost, then use Charles to set up a proxy server. Then you go to the settings on your phone, go into Wi-Fi, long-press the network you are connected to, choose Modify Network, and enter the proxy settings Charles gave you.
In my case, nothing of these solutions works because Windows firewall blocks it, but putting a rule on the firewall hasn't effect.
The problem in my case is that my laptop is connected with Wifi and Windows had the Wifi connection like a Public network. I must to change the network connection to Private network. http://www.comofuncionatodo.net/tecnologia/informatica/como-cambiar-de-red-publica-a-red-privada-en-windows-10/
I agree with the other answers as good approaches if you don't want to expose your DEV webservice on the internet. However, it's much easier if you do just expose the webservice. There's a number of free DNS services, but I've found no-ip to be the easiest to set up. I use it for exactly the purpose that you asked about; so I can test with my DEV webservice on a real device.
If you choose to go with no-ip (I have no affiliation with that company, it's just the one I've used and am familiar with), you can get a free publicly accessible URL like http://MyExampleWebServer.no-ip-org, and no-ip has a utility you can install so even if you're behind a dynamic IP, it will always keep the correct external IP associated with that URL. If you're working from your house, then you'd just need to make sure you port forward traffic from port 80 to your internal 192.x.x.x IP address (or whatever port you use; maybe 443 for ssl).
It's as easy as that, and now you can hit that webservice from any device that can access the internet.
I haven't worked with it, but I believe dyndns also offers a similar service.
This solution is for GAE development server in Eclipse
Step 1: Get the LAN IP
Goto your Windows Command Console (Press Win+R, then type "cmd"). In the console, enter "ipconfig". You will see a list of display. Under Wireless LAN adapter Wi-Fi, get the IPv4 Address. It will be something 192.168.x.x
LAN IP : 192.168.x.x
Step 2:
Go to Eclipse, Open the Configured server
Under Properties of GAE Development Server -> Local Interface address to bind to, enter the LAN IP address, and save.
Step 3:
Now you can access the GAE server by
http://192.168.x.x:8888/
8888 - Refers to the Port Number, as mentioned in the GAE development server
In order to access local web services using their own server hosts rather than IP addresses with ports, do these following steps:
Make sure your Android device and your local machine are on the same network.
Install SquidMan on your Mac, Linux, or any other Proxy Server.
Configure the proxy server's HTTPPort (ex. 5555) and clients (ex. 192.168.0.0/24) to your own network mask, and run the proxy server.
You are either using the web services in:
a. A web browser: Configure the proxy settings of your Android device from Modify WiFi networks.
b. Android application:
Set up the Proxy for your HTTP client. If you are using Volley, check this out: Volley Behind a Proxy server.
You can now connect to it by using whatever URL you are using on your host to connect to the web service (ex. http://my-local-machine.com)
Hint: If you got 4xx response codes, make sure your web service allows connections from other non-local-hosts.
If you are referring your localhost on your system from the Android emulator then you have to use
http://10.0.2.2:8080/
Because Android emulator runs inside a Virtual Machine(QEMU) therefore here 127.0.0.1 or localhost will be emulator's own loopback address.