User`s manual

Disconnect if no activity
The CT-5611T can be configured to disconnect if there is no activity for a period of
time by selecting the
Dial on demand check box. When the checkbox is ticked, you
need to enter the inactivity timeout period. The timeout period ranges from 1
minute to 4320 minutes.
PPP IP Extension
The PPP IP Extension is a special feature deployed by some service providers. Unless
your service provider specially requires this setup, do not select it.
The PPP IP Extension supports the following conditions:
z Allows only one PC on the LAN
z The public IP address assigned by the remote side using the PPP/IPCP protocol
is actually not used on the WAN PPP interface. Instead, it is forwarded to the
PC’s LAN interface through DHCP. Only one PC on the LAN can be connected to
the remote, since the DHCP server within the ADSL router has a single IP
address to assign to a LAN device.
z NAPT and firewall are disabled when this option is selected.
z The ADSL router becomes the default gateway and DNS server to the PC
through DHCP using the LAN interface IP address.
z The ADSL router extends the IP subnet at the remote service provider to the
LAN PC. That is, the PC becomes a host belonging to the same IP subnet.
z The ADSL router bridges the IP packets between WAN and LAN ports, unless the
packet is addressed to the router’s LAN IP address.
Enable NAT checkbox
If the LAN is configured with a private IP address, the user should select this
checkbox. The NAT submenu on the left side main panel will be displayed after
reboot. The user can then configure NAT-related features after the system comes up.
If a private IP address is not used on the LAN side (i.e. the LAN side is using a public
IP), this checkbox should be de-selected. When the system comes back after reboot,
the NAT submenu will not be displayed on the left main panel.
Enable Firewall
The Internet has made large amounts of information available to the average
computer user at home, in business and in education. For many people, having
access to this information is no longer just an advantage, it is essential. Yet
connecting a private network to the Internet can expose critical or confidential data
to malicious attack from anywhere in the world. Users who connect their computers
to the Internet must be aware of these dangers, their implications and how to
protect their data and their critical systems. Firewalls can protect both individual
computers and corporate networks from hostile intrusion from the Internet, but must
be understood to be used correctly.
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