User`s guide

Appendix B: Internet Protocol Denitions

ARP = Address Resolution Protocol - Used to determine Ethernet

(MAC) address when a device starts to communicate with another. The

IP address is known and a broadcast is used to request the specic

IP addressed device to respond with its MAC address, so further

communication can be specically addressed between the two.

DHCP = Dynamic Host Conguration Protocol - Used when a new IP

device is added to a LAN and it needs to get information about the IP

addresses used on that LAN. One DHCP server must be present on the

LAN to provide a response to a DHCP request transmitted to a broadcast

address and inform the new device of several conguration details. A

DHCP server is not required on a LAN, but if it does not exist, all the

devices on the LAN must be manually congured. Much information can

be provided by the DHCP server, the LanScaper™ requests and uses:

- an IP address for itself (My IP)

- the IP address of the DHCP server on the LAN

- the Netmask in use

- the IP address of the Router on the LAN

- the IP address of the DNS server accessible from the LAN

DNS = Domain Name Server - Provides translation of URL addresses

(www.yahoo.com) to IP addresses (66.218.71.89), so that access to

the internet devices can be requested using human-understandable

identiers. DNS servers are found on the internet, and thus are of

interest to the LanScaper™ because accessing (PINGing) the DNS

server proves that the LanScaper™ can access a device on the WAN.

Gateway = Router - see below

IP = Internet Protocol - Actually TCP/IP = Transmission Control Protocol/

Internet Protocol, but commonly abbreviated to IP. Communications

addressing scheme dened by DARPA (Defense Advanced Research

Projects Agency) to control the publicly accessed internet network.

IP Address - Specic number assigned to a single device to allow it

to be uniquely identied on the network to which it is connected. On a

LAN, the IP address must be within the range of addresses dened for

that LAN by the Network Mask in use. On the internet, all IP addresses

must be universally unique to allow addressing that specic device. IP

addresses consist of 4 hexadecimal digits that are commonly written in

“dotted decimal” format. 192.168.254.4 is an example. Note that each

set of decimal numbers divided by the periods must be in the range of

0-255 as they represent hexadecimal values of 00-FF.