Lantronix EDS16PR User Manual

Page of 158
C: Networking and Security 
EDS Device Servers User Guide 
144 
 
Tunneling 
Tunneling provides a way to create a connection between two serial devices across an 
untrusted network so the devices can share data. The sharing of information is achieved 
through a direct connection (or “serial tunnel”) between the two devices that 
encapsulates, authenticates, and encrypts the serial data into TCP packets and sends 
them across the Ethernet network. In this way, two previously isolated and non-
networked devices can securely and effectively communicate and exchange information 
and operate with existing installed software applications or devices that are configured to 
run independent of an Ethernet network. And because the tunnel can be secure, anyone 
who tries to monitor the conversation between the two devices would see encrypted, 
unintelligible data. 
The figure below shows how a pair of device servers can be used in tandem to provide 
transparent serial tunneling across an Ethernet network. In this example, a POS device in 
a store collects data and sends it to a device server attached to a POS serial port. The 
device server forwards the collected data, through an encrypted tunnel established over 
the Ethernet network, to a device server connected to a remote PC. The data received at 
the remote device server is decrypted and forwarded to the PC’s serial port and received 
at the remote PC. In this way, serial data that goes in one end comes out at the other 
end. 
Example of an Encrypted Tunnel