User's Manual

UTT Technologies Chapter 6 Basic Setup
http://www.uttglobal.com Page 116
 Default Gateway: It specifies the IP address of the default gateway for a DHCP client.
In most cases, this address should be the same with the Device¶s LAN IP address,
that is, the Device is used as the default gateway for the LAN hosts.
 Lease Time: It specifies a length of time (in seconds) during which a client host can
use an assigned IP address. If the lease expires, the client is automatically assigned
a new dynamic IP address. Before the lease expires, the client typically needs to
renew its address lease assignment with the server. The default value is 3600
seconds.
 Primary DNS Server: It specifies the IP address of the primary DNS server that is
available to a DHCP client. If you have already set the Primary DNS Server through
the Quick Wizard or in the Basic > WAN page, the Device will automatically set up
the same value here.
 Secondary DNS Server: It specifies the IP address of the secondary DNS server
that is available to a DHCP client. If you have already set the Secondary DNS
Server through the Quick Wizard or in the Basic > WAN page, the Device will
automatically set up the same value here.
¾ Save: Click it to save the DHCP server settings.
Note
If you want a LAN host to obtain an IP address and other TCP/IP parameters from the
Device¶s built-in DHCP server, please select the Obtain an IP address
automatically option in the TCP/IP properties dialog box on the host.
6.4.2 DHCP Auto Binding
If the hosts change frequently on your LAN, it is very troublesome to configure DHCP
manual bindings. Using ARP Spoofing Defense (see section 12.1.1 Internal Attack
Defense) feature also needs periodic maintenance. So usually there are some users who
can¶t access the Device and Internet. To deal with these issues, the Device provides
DHCP auto binding feature.
Once the DHCP auto binding is enabled, the Device will immediately scan the LAN to
detect active hosts connected to the Device, learn dynamic ARP information and bind the
related valid IP and MAC address pairs. After that, when a client host obtains an IP
address from the Device that acts as a DHCP server, the Device will immediately bind this
host¶s IP and MAC address pair. So it can effectively protect the Device and LAN hosts
against ARP Spoofing.