User manual

set realport
Chapter 2 Command Descriptions 185
set realport
Devices
supported
This command is supported in all Digi Connect products.
Purpose Configures and displays RealPort-related settings.
Required
permissions
For Digi Connect products with root and non-root (normal) users, the root
user can configure RealPort settings. The normal user can display
RealPort settings.
Syntax Configure RealPort settings
set realport [keepalive={on|off}]
[exclusive={on|off}]
Display current RealPort settings
set realport
Options keepalive={on|off}
Enables or disables sending of RealPort keepalives. RealPort keepalives
are messages inside the RealPort protocol, sent approximately every 10
seconds, to tell whoever is connected that the connection is still alive.
RealPort keepalives are different from TCP keepalives, which are done
at the TCP layer, and configurable. The default is “on.”
As RealPort keepalives generate additional traffic--several bytes every
10 seconds--this option allows you to turn them off. RealPort keepalives
may cause issues in environments that are metered for traffic, or that do
not require this type of mechanism. In situations such as cellular/mobile
wireless communications, when you are paying by the byte, such
additional traffic is undesirable when a TCP keepalive can do the same
job, and only when the connection is idle.
If you want to have the RealPort keepalive set to “off;” consider using a
TCP keepalive instead. This is because if the link is not closed properly,
you could end up with your port being “locked up” with a dead TCP
session, which is why RealPort keepalives were implemented in the first
place.
exclusive={on|off}
Enables or disables exclusive mode for RealPort connections. Exclusive
mode allows the Digi Connect device to close an existing RealPort
connection and establish a new one immediately upon a new connection
request from the same IP address. This mode is useful when using
RealPort over wide area networks, which can be unstable and where you
are charged by the byte (such as cellular or satellite), and you do not wish
to incur costs for keep-alive traffic. Exclusive mode allows your
application to retain continuity when temporary, unexpected interruptions
in network connectivity occur.
Example #> set realport keepalive=on