I have come across some devices by a companay called "Lantronix" that produce 'Secure Access Servers'.

The description makes it sound like they are physical devices that pretty much do what Terminal programs like PuTTy, SecureCRT, HyperTerminal, etc... do?

"Lantronix console managers provide effective in-band and out-of-band management solutions for IT equipment in data centers, network edges, colocations, remote sites, branch offices, and engineering test labs. These products provide network and system managers unsurpassed ability to securely and remotely manage IT assets including switches, routers, storage devices, security appliances, power management devices (PDU, UPS), telecom equipment, and servers even during system or network outages to maintain business continuity."

Is that the case?


sound like they are physical devices that pretty much do what Terminal programs like PuTTy, SecureCRT, HyperTerminal, etc... do?

No. A setup using the access server would look like this:

+-----------+                 +-----------+
|           |   Serial        |           |                +-----------+
| Switch/   | (RS232/USB)     |           |     IP         |           |
| Router/   +-----------------+ Lantronix +-------...------+ Laptop/PC |
| etc.      |                 |           |                |           |
|           |       +---------+           |                +-----------+
+-----------+       |         +-----------+
+-----------+       | Serial
|           |       |(RS232/USB)
| Switch/   |       |
| Router/   +-------+
| etc.      |
|           |

You still have to run PuTTY etc. on your Laptop/PC to connect to the Lantronix. You distinguish between devices by specifying different TCP port numbers.

So, why not just connect the switch/router/etc. directly over IP to the Laptop/PC and eliminate the need for the access server? Well, because there are some operations that can only be performed over the device's serial interface. One example is bootloader/rommon upgrades. Another is to gather early device boot up logs at which point the device's Networking stack is not yet ready and therefore syslog is not usable.

  • 1
    or, you want a secure, out-of-band, path to the device(s)
    – Ricky
    Oct 22 '17 at 5:19

I've used a lot of their equipment: various kinds of serial port to TCP/IP devices. They're very flexible and very reliable.

Typical uses are to convert a device (perhaps a weather station) outputting messages once a minute over RS-232 to send UDP packets to a given port on a given server. Another would be to connect via telnet to an RS-232 device, perhaps a modem. Or a router console socket.


EDIT I forgot to add the virtual com port, where a PC uses the Lantronix device as if it was a local serial port, without having to connect to it by telnet/putty/whatever. Connection is RFC 2217 or various other methods.


I know Lantronix as a maker of COM servers - essentially, they allowed you to connect a simple serial port to a network.


Terminal server describes this functionality of local console port access which allows you to power cycle and/or configure the box remotely. HP's iLOM ports offers this capability all baked in. Cisco's UCS servers offer something called CIMC, Cisco Integrated Management Controller.

For it to be out-of-band, the network used to access the terminal server must be separate from the network provided by the equipment you are accessing.

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