NetworkInfo

NetworkInfo allows you to quickly obtain information about your network, even if you are not connected to the network itself. See which devices are online or offline, send a quick ping to a device. Name devices for easy recognition. Group devices in categories which you define yourself. Organize categories and network devices by drag and drop.
This app uses an Secure Shell (SSH) connection to your router (or any SSH-enabled machine) that can be reached via the network by this devices. This could be via wifi on your home network, or, if your router/machine is exposed to the internet, from any network location on the internet that allows outbound SSH connections.
The SSH connection is used to run (linux) commands directly on the router/machine to obtain information about the network devices connected to it. Your router or other machine must be configured to allow SSH connections (act as an SSH server). You need to know the credentials (login details) and supply them to this app.
The login credentials are stored on this device by this app in an encrypted fashion, using the Android Key Store facility. It is recommended to use the key-based authentication method instead of passwords (when using key based authentication, the credentials by design never leave the device).
The commands used through the SSH connection are arp, ping, grep, sort, awk, head, cut and the /sys/class/net interface (which is the case on most Linux-based system). The aforementioned Linux tools should be available after login via SSH (e.g., be in the $PATH on the SSH server after login).
Most home network routers run some form of Linux and provide these tools or can be extended to use them (e.g. using OpenWRT or Freetz).
If a firewall is active on your network, it must be set to allow connections to the SSH server. Usually this involves unblocking port 22 (the standard SSH server port). SSH servers can also be configured to use another port. In that case the firewall must be set accordingly.
At the moment, this app only supports devices with IP4 addresses in the range XXX.XXX.XXX.0-255.