Ethernet Interfaces - D-Link NetDefendOS User Manual

In addition, NetDefendOS provides two special logical interfaces which are named any and core.
The meaning of these are:
• any represents all possible interfaces including the core interface.
• core indicates that it is NetDefendOS itself that will deal with traffic to and from this interface.
Examples of the use of core are when the NetDefend Firewall acts as a PPTP or L2TP server or
responds to ICMP "Ping" requests. By specifying the Destination Interface of a route as core,
NetDefendOS will then know that it is itself that is the ultimate destination of the traffic.
Disabling an Interface
Should it be desirable to disable an interface so that no traffic can flow through it, this can be
done with the CLI using the command:
gw-world:/> set Interface Ethernet <interface-name> -disable
Where <interface-name> is the interface to be disabled.
To re-enable an interface, the command is:
gw-world:/> set Interface Ethernet <interface-name> -enable
Disabling interfaces can also be done through the Web Interface.

3.4.2. Ethernet Interfaces

The IEEE 802.3 Ethernet standard allows various devices to be attached at arbitrary points or
"ports" to a physical transport mechanism such as a coaxial cable. Using the CSMA/CD protocol,
each Ethernet connected device "listens" to the network and sends data to another connected
device when no other is sending. If 2 devices broadcast simultaneously, algorithms allow them to
re-send at different times.
Ethernet Frames
Devices broadcast data as Ethernet frames and other devices "listen" to determine if they are the
intended destination for any of these frames. A frame is a sequence of bits which specify the
originating device plus the destination device plus the data payload along with error checking
bits. A pause between the broadcasting of individual frames allows devices time to process each
frame before the next arrives and this pause is progressively smaller with the faster data
transmission speeds found in normal Ethernet, then Fast Ethernet and finally Gigabit Ethernet.
Physical Ethernet Interfaces
Each logical NetDefendOS Ethernet interface corresponds to a physical Ethernet interface in the
system. The number of interfaces, their link speed and the way the interfaces are realized, is
dependent on the D-Link hardware model.
Note: Usage of the terms "interface" and "port"
The terms Ethernet interface and Ethernet port can be used interchangeably. In this
document, the term Ethernet interface is used throughout so it is not confused with the
port associated with IP communication.
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Chapter 3: Fundamentals