B&B Electronics VFG3000 - Manual - Manual (Page 50)

W ORKING WITH M ODEMS V LINX F IELDBUS G ATEWAY M ANAGER U SER M ANUAL
P AGE 34
A
DDING A
D
IAL
-O
UT
C
ONNECTION
Dial-out connections are added exactly as above, except that the PPP and Modem Client
driver should be selected for the required port. The configuration options for this modem are
shown below…
The modem has the following properties that are distinct from those for dial-in connections…
• The Connect Using property is as for dial-in connections, with the addition of
support for GPRS connections via a GSM modem. These connections differ
from CSD connections in that they achieve much higher speeds, and are
typically charged on the basis of how much data is transferred rather than how
long the connection is maintained. GPRS connections may thus be configured
for permanent connection, unless there is a need to provide downtime to allow
SMS messages to be transferred.
• The No Firewall property is used to turn off the firewall protection that is
otherwise provided for dial-out connections. This protection prevents incoming
connections from being made to this interface, and prevents the Gateway from
sending certain diagnostic packets that might either provide a hacker with
information about the system, or might be used by an attacker to keep a
connection active in the absence of actual data transfer. If you are connecting
directly to the Internet by means of this connection, you should not normally turn
off the firewall. The firewall should be disabled only for connections to
corporate networks or to other controlled environments.
• The Connection Type property is used to indicate whether you want this
connection to be permanently maintained, or whether you want it to be
established automatically when an attempt is made to transfer data to hosts that
are reachable via this interface. If you select an on-demand connection, you must