UTT Technologies Chapter 11 Firewall
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Page 179
address 192.168.16.36 is performing SYN flood attack, and then randomly discard
the further SYN packets from that source to that destination. In most cases, leave
Threshold
the default value.
Enable ARP Spoofing Prevention:
It allows you to enable or disable ARP spoofing
defense. If you select the check box to enable this feature, and then bind all the
IP/MAC address pairs of the LAN hosts (configured in
the
Security > IP/MAC
Binding
page), it will effectively protect the Device against ARP spoofing attack.
ARP Broadcast Interval:
It specifies the time interval at which the Device
periodically broadcasts gratuitous ARP packets. These gratuitous ARP packets are
used to inform the LAN hosts the correct MAC address of the Device
’s LAN interface,
so the LAN hosts can effectively defense ARP spoofing attack. It should be multiple of
10 between 100 and 5000 milliseconds.
2. Access Restriction
Enable Device Access Restriction
: It allows you to enable or disable device Access
Restriction. Select the check box to restrict
LAN hosts’ access to the Device through
LAN interface, so it will protect the Device against internal DDoS attacks. The Access
Restriction rules are as follows:
1) Allow any LAN host to use ICMP to access the Device.
2) Allow any LAN host to access the UDP port 53, 67 or 68 of the Device, to ensure
that the Device
’s DNS proxy, DHCP server and DHCP client can operate
properly.
3) Only allow the LAN hosts that belong to the range specified by
Start IP
… to…
to
access the web or telnet service provided by the Device, but block the other
hosts.
4) Block LAN hosts from accessing any other services provided by the Device.
Start IP
… to…:
It specifies an address range of the allowed LAN hosts. When
Enable Device Access Restriction
is selected, only the LAN hosts that belong to
this range can access the web or telnet service provided by the Device.
3. Others
Enable Port Scanning Prevention:
It allows you to enable or disable Port Scanning
Prevention.
If you select this check box to enable this feature, it will effectively protect
the Device against port scanning attack. After you enable this feature, if a LAN host
continuously sends the SYN packets to different ports on a remote host, and the
number of ports exceeds 10 at the specified time interval (set by the
Threshold)
, the
Device will consider that the LAN host is performing port scanning attack, and then
randomly discard the further SYN packets from it to that destination host. In most
cases, leave the
Threshold
the default value.