Dhcp - Linksys LGS308 User Manual

Up to eight DNS servers can be defined.
To add a DNS server:
1. Click Add.
2. Enter the parameters.
• IP Version—Select IPv6 or IPv4.
IPv6 Address Type—Select the IPv6 address type (if IPv6 is used).
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• Interface — If the IPv6 address type is Link Local, select the interface
through which it is received.
• DNS Server IP Address — Enter the DNS server IP address.
Preference — Select a value that determines the order in which the domains are
•
used (from low to high). This effectively determines the order in which unqualified
names are completed during DNS queries.
3. Click Apply. The DNS server is saved to the Running Configuration file.

DHCP

DHCP snooping provides a security mechanism to prevent receiving false DHCP response
packets and to log DHCP addresses. It does this by treating ports on the device as either trusted
or untrusted.
A trusted port is a port that is connected to a DHCP server and is allowed to assign DHCP
addresses. DHCP messages received on trusted ports are allowed to pass through the device.
An untrusted port is a port that is not allowed to assign DHCP addresses. By default, all ports are
considered untrusted until you declare them trusted in the Interface Settings page.
Option 82
Option 82 (DHCP Relay Agent Information Option) passes port and agent information to a central
DHCP server, indicating where an assigned IP address physically connects to the network.
The main goal of option 82 is to help to the DHCP server select the best IP subnet (network pool)
from which to obtain an IP address.
The following Option 82 options are available on the device:
o Global — The IPv6 address is a global Unicast IPV6 type that is visible and
reachable from other networks.
o Link Local — The IPv6 address uniquely identifies hosts on a single network
link. A link local address has a prefix of FE80, is not routable, and can be
used for communication only on the local network. Only one link local
address is supported. If a link local address exists on the interface, this
entry replaces the address in the configuration.
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