KTI Networks KGS-2421, Руководство пользователя

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specific information from a DHCP reply packets when forwarding server DHCP packets to a
DHCP client. The DHCP server can use this information to implement IP address or other
assignment policies. Specifically the option works by setting two sub-options: Circuit ID
(option 1) and Remote ID (option2). The Circuit ID sub-option is supposed to include
information specific to which circuit the request came in on. The Remote ID sub-option was
designed to carry information relating to the remote host end of the circuit.
The definition of Circuit ID in the switch is 4 bytes in length and the format is "vlan_id"
"module_id" "port_no". The parameter of "vlan_id" is the first two bytes represent the VLAN
ID. The parameter of "module_id" is the third byte for the module ID (in standalone switch it
always equal 0, in stackable switch it means switch ID). The parameter of "port_no" is the
fourth byte and it means the port number.
The Remote ID is 6 bytes in length, and the value is equal the DHCP relay agent¡¦s MAC
address.
DHCP Snooping
DHCP Snooping is used to block intruder on the untrusted ports of DUT when it tries to
intervene by injecting a bogus DHCP reply packet to a legitimate conversation between the
DHCP client and server.
DNS
DNS is an acronym for Domain Name System. It stores and associates many types of
information with domain names. Most importantly, DNS translates human-friendly domain
names and computer hostnames into computer-friendly IP addresses. For example, the domain
name www.example.com might translate to 192.168.0.1.
DoS
DoS is an acronym for Denial of Service. In a denial-of-service (DoS) attack, an attacker
attempts to prevent legitimate users from accessing information or services. By targeting at
network sites or network connection, an attacker may be able to prevent network users from
accessing email, web sites, online accounts (banking, etc.), or other services that rely on the
affected computer.
Dotted Decimal Notation
Dotted Decimal Notation refers to a method of writing IP addresses using decimal numbers
and dots as separators between octets.
An IPv4 dotted decimal address has the form x.y.z.w, where x, y, z, and w are decimal
numbers between 0 and 255.
DSCP
DSCP is an acronym for Differentiated Services Code Point. It is a field in the header of IP
packets for packet classification purposes.
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