Which is the best appplication way to give access to free wifi to particular applications only (say whataspp)?
Yes, its possible through a (logical)firewall between the wifi network and the gateway.
Whatsappp-packets can be detected by tcp port number and destination ip.
there are some good wifi/gateway/firewall combi-devices, e.g all openWRT and routerOS devices
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I need to create a wireless network with no Internet access with a Pi, because I need to communicate to it with an Android smartphone and a laptop, but being the RPi the highest step in the network hierarchy.
I've found -and tried- that I can do an adhoc network, but I am unable to connect to it with the smartphone. The other alternative is creating a Wi-Fi hotspot, with no NAT, but I don't really have a deep knowledge on networks so I'm really lost in which IP adresses I have to set.
I've followed this tutorial, and found it really useful. Could anyone tell me what should I modify from it to make it only local -apart from not doing the NAT?
The Rapsberry Pi 3 has built in Wi-Fi that can serve as an access point. Based on my experience, with the Pi acting as an access point, you should be able to connect to any device, be it Android or not.
The Pi will act as access point and serve as a DHCP daemon, assigning and handling IP addresses to any devices that connect to it. This will be a standalone network and will not be able to share an Internet connection unless you bridge it. Follow this tutorial up until the Internet sharing part:
https://www.raspberrypi.org/documentation/configuration/wireless/access-point.md
Also, it would be better to ask this in the Raspberry Pi stack exchange.
I'd like to know that a specific device (phone/tablet) has joined my WiFi network created by ESP8266 microcontroller. It shouldn't require any installed apps on that phone/tablet, if possible, to simplify the whole setup.
So I think I need to somehow identify connected clients, and MAC is not an option because it is subject to change randomly on, say, Apple devices.
Maybe it's possible to collect host names of connected clients?
I know that Windows and Ubuntu clients send their host names when getting IP from DHCP server (see here). Also, it's possible to find such information on, say, home Wi-Fi router admin web page (i.e. host names, their IPs and MACs).
I'm running DHCP server on ESP8266, but I haven't found any API that allows to get peer host name (i.e. reverse DNS). Does ESP8266 support getting such information?
I am not an expert of the network domain.
Today I have a network with a connection to the Internet. Some computers use an ethernet connection, others use the WIFI.
I wish to monitor the network because we have a slow connection.
I plan to add a switch with SNMP in front of my modem.
If I connect an access point wifi on the switch, would I be able to differentiate the different computers connected in wifi ?
Thank you,
Any network equipment that has the BRIDGE-MIB RFC 1493 implemented will let you check which port is doing what on your network. You would want a switch/router that is also an access point, or if separate equipment, then the access point needs the BRIDGE-MIB.
I'm using Embarcadero RAD Studio Delphi XE8.
Multi-Device Application app tethering components are designed for traditional WiFi and Bluetooth coupling. Does it support also Internet connections?
I would like to try to make small p2p app. I'm using App tethering via Wifi but I would like to connect App tethering via internet connection.
how to do that ?
Taken from the documentation
Connecting to Applications Outside Your Subnet
By default, both AutoConnect and DiscoverManagers perform the
discovery on the subnet of the local area network (LAN) where the
device running your application is. However, you can use their
optional parameter Target to override this behavior, and specify an IP
address or subnet: To specify an IP address to search for remote
managers, specify that IP address as the Target. To specify a subnet
of IP addresses, specify an IP address with a 0 as its fourth number.
For example, if you specify "192.168.4.0" as the Target, your manager
searches the 192.168.4.x subnet for remote managers. Note: You can not
specify wider subnets. For example, "192.168.0.0" is not supported.
In other words you need to use the IP address as the optional ATarget parameter of the mentioned calls. The differences to local tethering are minor, which I guess is why there are not many examples.
See the Embarcadero web site for more details
Try VPN connect two device. If your 2 device is same vpn (For ex: Softether , Openvpn). you can discover other device around the world. (Dont forget enable vpn server settings to discover other devices options)
I have got a couple of phones and another couple of PC's connected to a Wifi access point and need to send and receive messages between either of these, I mean anyone can send a message to anyone and receive a message from anyone.
I am willing to write apps on the phones(Symbian OS, S60 platform) or PC(Windows), but what I can't understand is how do I set up a client or server, since any one of these devices could be a client or server.
If I use sockets do I have to script for ServerSockets and also Sockets on each of these devices? Can I use the HTTP protocol?
Alternatively any standard protocol that I could use to implement this?
You would broadcast UDP packets which would arrive at every device on the Wifi network. You would have to invent your own protocol to decide on the identity of each device, since you wouldn't be able to easily infer the IP addresses of your network devices. Without writing an election algorithm you would find it difficult to use a client/server architecture, so just use point-to-point (P2P).
Google for UDP broadcasts and read the relevant RFCs at ietf.org.
It seems like you're looking for pretty typical peer-to-peer communication over IP. I suppose other requirements will dictate which transport you use (HTTP, raw sockets, etc), but yes: Each node will be both a client and a server. You could possibly use MDNS (http://www.multicastdns.org/) to help the nodes find eachother in an ad-hoc manner.