Many network assets are not covered by the SMB/RPC/SSH protocols. These are the assets that either don't run Windows or Unix-based operating systems, or run unsupported systems, or run simple Unix-based systems without the SSH interface. These could include network printers, managed switches, routers, xDSL modems, IP phones, wireless access points, etc. Most often these devices support either SNMP or Telnet or sometimes both, and in such cases they can be scanned by TNI using these protocols.
Scanning SNMP devices
TNI considers any devices that could not been scanned via other protocols as potentially SNMP-compatible, therefore, it tries to scan them using SNMP, if it's allowed by the scanner settings. By default, when the public community is specified, it tries several well-known communities until it succeeds:
Scanning Telnet devices
If a Telnet login is specified, TNI checks if TCP port 23 is open. If positive, TNI will try to scan the device using the Telnet protocol.
Currently TNI supports Telnet scanning for the following systems: BusyBox.