D-Link DFL-800-AV-12 User Manual - Page 70

Static ARP Entries, Published ARP Entries, 4.4. Static and Published ARP, Entries

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3.4.4. Static and Published ARP Entries Chapter 3. Fundamentals NetDefendOS supports defining static ARP entries (static binding of IP addresses to Ethernet addresses) as well as publishing IP addresses with a specific Ethernet address. Static ARP Entries Static ARP items may help in situations where a device is reporting incorrect Ethernet address in response to ARP requests. Some workstation bridges, such as radio modems, can have such problems. It may also be used to lock an IP address to a specific Ethernet address for increasing security or to avoid denial-of-service if there are rogue users in a network. Note however, that such protection only applies to packets being sent to that IP address, it does not apply to packets being sent from that IP address. Example 3.16. Defining a Static ARP Entry This example will create a static mapping between IP address 192.168.10.15 and Ethernet address 4b:86:f6:c5:a2:14 on the lan interface: CLI gw-world:/> add ARP Interface=lan IP=192.168.10.15 Mode=Static MACAddress=4b-86-f6-c5-a2-14 Web Interface 1. Go to Interfaces > ARP > Add > ARP 2. Select the following from the dropdown lists: • Mode: Static • Interface: lan 3. Enter the following: • IP Address: 192.168.10.15 • MAC: 4b-86-f6-c5-a2-14 4. Click OK Published ARP Entries NetDefendOS supports publishing ARP entries, meaning that you can define IP addresses (and optionally Ethernet addresses) for an interface. NetDefendOS will then provide ARP replies for ARP requests related to those IP addresses. This can serve two purposes: • To give the impression that an interface in NetDefendOS has more than one IP address. • To aid nearby network equipment responding to ARP in an incorrect manner. This use is however less common. The first purpose is useful if there are several separate IP spans on a single LAN. The hosts on each IP span may then use a gateway in their own span when these gateway addresses are published on the corresponding NetDefendOS interface. Another use is publishing multiple addresses on an external interface, enabling NetDefendOS to statically address translate communications to these addresses and send it onwards to internal servers with private IP addresses. 70

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NetDefendOS supports defining static ARP entries (static binding of IP addresses to Ethernet
addresses) as well as publishing IP addresses with a specific Ethernet address.
Static ARP Entries
Static ARP items may help in situations where a device is reporting incorrect Ethernet address in
response to ARP requests. Some workstation bridges, such as radio modems, can have such
problems. It may also be used to lock an IP address to a specific Ethernet address for increasing
security or to avoid denial-of-service if there are rogue users in a network. Note however, that such
protection only applies to packets being sent to that IP address, it does not apply to packets being
sent from that IP address.
Example 3.16. Defining a Static ARP Entry
This
example
will
create
a
static
mapping
between
IP
address
192.168.10.15
and
Ethernet
address
4b:86:f6:c5:a2:14
on the
lan
interface:
CLI
gw-world:/>
add ARP Interface=lan IP=192.168.10.15 Mode=Static
MACAddress=4b-86-f6-c5-a2-14
Web Interface
1.
Go to
Interfaces > ARP > Add > ARP
2.
Select the following from the dropdown lists:
Mode:
Static
Interface:
lan
3.
Enter the following:
IP Address:
192.168.10.15
MAC:
4b-86-f6-c5-a2-14
4.
Click
OK
Published ARP Entries
NetDefendOS supports
publishing
ARP entries, meaning that you can define IP addresses (and
optionally Ethernet addresses) for an interface. NetDefendOS will then provide ARP replies for
ARP requests related to those IP addresses.
This can serve two purposes:
To give the impression that an interface in NetDefendOS has more than one IP address.
To aid nearby network equipment responding to ARP in an incorrect manner. This use is
however less common.
The first purpose is useful if there are several separate IP spans on a single LAN. The hosts on each
IP span may then use a gateway in their own span when these gateway addresses are published on
the corresponding NetDefendOS interface.
Another use is publishing multiple addresses on an external interface, enabling NetDefendOS to
statically address translate communications to these addresses and send it onwards to internal
servers with private IP addresses.
3.4.4. Static and Published ARP
Entries
Chapter 3. Fundamentals
70