Routed Versus Bridged Dsl Modems - McAfee SG310 Administration Manual

Network Setup menu options
ADSL

Routed versus bridged DSL modems

Before you configure ADSL, check whether your DSL modem is in a routed or bridged mode. Many ISPs
preconfigure this for your convenience. Often you can change the mode to suit your needs. Check with your
ISP to determine if they can accommodate changing between bridged and routed mode or vice versa on the
modem they supplied.
If your DSL modem is in routed mode, then all PPTP/PPPoE and similar login and connection considerations
are addressed from inside the modem. You should then connect your UTM Firewall appliance in Direct or
DHCP mode to your DSL modem, and will not be required to enter any additional ADSL information on the
UTM Firewall Management Console.
Note: Do not use ADSL configuration on the UTM Firewall Management Console if your modem is in routed mode.
There are some advantages to the bridged mode:
• Your UTM Firewall appliance becomes the portal to the Internet
• You do not have to port-forward service in two places (on the DSL modem and on the UTM Firewall
appliance).
The ADSL configurations listed here generally work best when your DSL modem is in bridged mode.
Note: PPPoA is not supported. If your ISP only supports PPPoA, the DSL modem must be configured in routed
mode.
If your ISP only support PPPoA, the UTM Firewall appliance needs to be configured with either DHCP or a
static address so it can communicate with the upstream router, which is your DSL modem.
ADSL configuration methods
You can configure DSL to establish a connection to your ISP using the following methods:
• Auto detect: If you are unsure of your ADSL connection type, the UTM Firewall appliance can attempt
to Auto detect ADSL connection type. The appliance is unable to detect the PPTP connection type. Refer
to the procedure Autodetecting your ADSL
• PPPoE: Select this method if your ISP uses user name and password authentication to access the
Internet. Refer to the procedure
• PPTP: Select this method if you have a dial-up VPN connection to the Internet provided by your ISP. Refer
to the procedure Connecting ADSL via
• DHCP: Select this method if your ISP does not require a user name and password, or your ISP provides
a dynamic IP address. Refer to the procedure
• Manually Assign Settings: Select this method if your ISP has given you a static IP address or address
range. Refer to the procedure
Prerequisites
If you have not already done so, connect the appropriate network port of your UTM Firewall appliance to
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your DSL modem.
Power on the DSL modem and give it some time to initialize. Ensure the Ethernet link LEDs are illuminated
2
on both the UTM Firewall appliance (if applicable to the model) and DSL modem. Do not continue until it
has reached the line sync state and is ready to connect. Most modems have a sync/line sync LED that
indicates whether or not the modem is talking to the DSLAM (Digital Subscriber Line Access Multiplexer)
of the telephone exchange. For more information on LEDs, refer to the appropriate LED topic for your UTM
Firewall model in Chapter 1,
Access the ADSL connections page so that you can configure your DSL connection. See
3
ADSL connection methods
McAfee UTM Firewall 4.0.4 Administration Guide
connection.
Connecting ADSL via
PPTP.
Connecting ADSL via
Manually assigning your ASDL
Introduction.
page.
PPPoE.
DHCP.
settings.
Accessing the
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