Lantronix ETS Reference Manual - 5.3.1 Dialback
Ports
Other Port Characteristics
5-11
Dial into the ETS again. The port should have been reset, and should no longer be connected to the network
host. If not, the modem is incorrectly asserting DSR/CD, or there is a wiring problem.
If outbound calls are to be supported, connect to the modem’s service with the Connect command. In many
cases the Connect Local command is a quick shortcut: dial a remote modem. After the modem connects,
log into the remote system.
In some configurations, it may not be possible to see the dial commands or the modem’s status messages.
If a modem fails to pick up the phone, DTR may not be wired correctly, or the modem may be configured
to ignore incoming calls. If modems fail to connect to each other, there could be a modem compatibility
problem. For example one modem’s configuration might require a special feature such as error correction
to complete connections. Verify both modem configurations, or try swapping one or both modems with
different models or different brands.
5.3 Other Port Characteristics
5.3.1 Dialback
Dialback allows a system manager to set up a dialback list of authorized users for incoming modem
connections. When a username matching one in the list is entered, the port will be logged out and the user
will be called back at the predefined number.
The Dialback system may be used for security purposes as well, but does not absolutely guarantee security.
See Dialback Security on page 5-16 for more information.
5.3.2 Dialup
It is frequently useful (or essential) for a LAT host to know whether a connection attempt is coming from a
modem or not. The LAT host will inquire about modem status when any connect is made, but you can
explicitly inform the host about modem status with the Dialup flag. When Dialup is enabled on a port, the
port will report that it is used for a dial-in modem if the LAT host asks. If you have any ports that will be
used exclusively for modem access, define this parameter.
Note:
The Dialup characteristic has no effect on non-LAT connections (Telnet, Rlogin,
and so on).
Some services or nodes may reject a connection because of its Dialup status due to the inherent security
concerns with modem connections. While this may seem like an annoyance, it is a security feature and
should be implemented if possible via the Dialup flag.
Figure 5-18: Setting the Dialup Flag
Local>> DEFINE PORT 4 DIALUP ENABLED