Is it possible to build a VPN without an actual server? - server

After searching online most places have stated that it is required to have a server to build a VPN, but I was wondering if it is possible to do it and have mobile devices connect to a dummy server? Without actually having something constantly running on a server.
I am currently developing an app that will make users connect to a VPN that blocks access to all sites.

Define "server". If you are worried about cost of hardware/power, bear in mind that a server is just a computer that hosts applications or data for clients to access and interact with. I currently have a Dell latitude e6400 running as an owncloud server in my basement. If you need something for testing you could simply utilize whatever old hardware you have laying around to set up the server side for your app to connect to, and turn it on whenever you are testing the app.

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Secure, local IoT Device Discovery using PWA without a remote server

I'm looking for a way to managing and controlling IoT devices without the (constant) need for a remote server to be part in it and with a PWA instead of a native application on the managing device. The resulting goal is an IoT device that keeps working when a product eventually goes obsolete (no more server running/allocated) and having an application that has PWA benefits like always up-to-date, easy to replicated and cheaply hosted on something like S3.
As an example, let's say I have one or more IoT devices of different classes like an ESP8266 and a Raspberry Pi for instance. Just as with any new IoT device I want to add it to the network and from there on manage its state from an app. The app in this case is a PWA instead of full blown native app.
1) Traditionally, in the initial setup a native app would scan for wifi networks, connecting automatically to one that has the right name. Using PWA's we are limited to just the "state" of the network. So users would have to manually switch to the network of the newly connected IoT device. This is okay.
2) Next up, the user would need to enter his/her wifi credentials. There might be methods to set this up automatically using a native app, but I don't believe this is the case on a PWA. This, also, is okay.
3) The device then restarts, tries to connect to the network set up in (2). If set up correctly it should get its IP using DHCP. And now things get difficult. I want to 'discover' that network from my PWA. There used to be a way to retrieve the IP from a device using the WebRTC API. but that since has changed to show an obfuscated mdns that resolves to localhost. The ip leak would have allowed for a browser based network scan, but that is no longer possible. I always hoped that Android would default to using a users router as a DNS server, but that is not the case. The result is that simply using an mDNS isn't an option either. I do not want user having to check their router, install an app like fing or do anything else that disrupts the flow from a UX perspective.
Step (3) needs to run every time the app starts so you'd want something reliable. Scanning for devices isn't possible using a PWA, so I need to find another method. I was thinking of something like the way Docker containers can find each other in between networks (see etcd for example), using a predefined key that is shared during installation. The problem with this, is that it requires a remote server to store the IPs attached to that key. I don't want that.
Ideas on how to solve this are very much appreciated! I want to be able to offer a solution that would work even when WAN is out. That being said, I am aware that a connection to a remote server is needed if the end user would want to enable any voice assistant or wants to control a device from WAN.

Electron app that opens a server or using sockets over the web

Im making an app that multiple players can connect to, but im brainstorming the best approach.
Im going to be using electron for the interface and then be able to use other computers to log in to website to join the game with multiple players.
I will use sockets to connect to each player, but what i am trying to figure out is whats the best approach for the interface.
Should i use express with electron to somehow connect to the same website the players are on?
Is it possible to make the electron app start up a server and have my website direct to the computer that is running the electron app?
Or my other option was to just continuously upload and download from a database, but I feel like that would not be very efficient.
You're on the right track. I would suggest using a WebSocket based server / client architecture.
The server application is continuously running and handles inter-player communication as well as providing a database. The database could be integrated in the server application as a starting point, and, depending on your needs concerning scalability, be extracted as a standalone service in the long run.
Client applications could then come in many forms (a website, a desktop application, a mobile app). Using electron is a great way to enable cross-platform desktop application development that is adaptable to any of these scenarios, possibly also enabling to extract the contained web application as either a hosted website or even mobile application (using, for example, react-native or nativescript).
Good luck!

iphone: a local server to test my app

the app that i'm developing, needs to interact with a server, to accomplish some operations: save user's data, retrieve data about other users, services and so on...
before paying to rent some space on a server, i'd like to test my app making it interact with a server located on my computer, simulating a real a LAMP server as a localhost.
did you ever tried to do the same? can you suggest me a LAMP server that i can use locally?
do you suggest any other solution in place of the one i'm seeking?
thanks for help
While the server is running make your requests to your own IP address. I'm fairly confident this will work while you are using the simulator, and likely it will also work from an app.
In terms of finding LAMP server software for the mac... you should check out MAMP which allows you to simulate a server on your mac.

How can I test an iOS App I am creating and simulate a Chinese user?

I am developing an app that will be used world-wide and have a co-worker who lives in China. He claims it takes a very long time to reach our server here in the US and I want to be able to use the app on my phone but through a VPN and proxy on my iPhone so it appears that I am in China. Is that possible?
Here you can find a list of Chinese web proxies.
You should also change your app so that it goes to through the proxy. This depends on how you are dealing with HTTP communication but if you google it, you will find many posts.
Keep in mind that a proxy will add a further delay in communication.
If you want to setup a VPN, have a look at this tutorial for setting up a VPN on your Mac and then connect the iPhone to it.

Bonjour - one server multiple clients - ios iPhone

Im developing an app where one iOS device act as "server", and other devices are acting like clients.
Im getting hard time with understanding if I can make this using Bonjour
If I make an example:
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All devices have same app installed. All users are connected to the same WIFI.
User must login into app, and when it does, chat rooms are populated from CMS (web server) from internet.
All of them see e.g. all "chat rooms". But at the beginning chat rooms are all read only. Anyone can browse these, but nobody can write into them.
When administrator (user with admin privileges) opens one of the chat rooms; all clients are now able to write into "open" chat rooms.
Of course when one user writes something down, the other users see the newest comment from him.
Administrator should see all clients in chat room but clients cannot see each other.
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All samples which I have found (WiTap, videos from WWDC,...) are using two devices only. I've installed WiTap on 4 devices. And I can establish connection and working "sample" game with two devices.
Can Bonjour service be used in such way that multiple cients are connected to one "server"?
Any hints are very welcome!
Yes, Bonjour can be used like that: for example Apache on Mac OS X has mod_bonjour so that web browsers can find a web server on the local network. That can mean having one server but multiple browsers: exactly the situation you describe.
One limitation is that the way Bonjour is configured in iOS means that the server and clients need to be on the same local network. It doesn't sound like the situation you describe is compatible with using Bonjour in that way, but then I also don't think you need to. You can use the DNS name of your chat server in the app, so any app can discover the server. The server can also be responsible for discovering which clients are connected and allowing people to find each other (indeed, I guess that's what the chat rooms are for).
This is a good place to start. http://mobileorchard.com/tutorial-networking-and-bonjour-on-iphone/ I have build the same Server and client with the help of chatty. But you will face one problem in iOS5 only, when the iphone will go to sleep mode, the socket connection lost. I am not able to solve this problem. So, looking for help. :)