Multitech RF500S Uživatelský manuál stáhnout pdf (Strana 25)

6.6 LocalHost Address

127.0.0.1 is a reserved loopback address. This is useful for testing to makes sure everything in the computer

is working correctly. This allows you to sent packet to the machine you are running on.

6.7 Gateway

Ethernet is local network. This means each device is in direct communication with all the other devices.

When devices need to discover information on the LAN they broadcast the request to everyone. This works

well on a small network but does not scale very well; the network quickly becomes overloaded with

broadcast messages. The solution to this problem is to interconnect individual LANs with a router. Routers

have the intelligence to connect multiple networks together. This confines the broadcast discovery

mechanism to a small group.

Routers have IP addresses like any other device. When a computer is unable to connect directly it forwards

the packet to the router. The router in turn sends it to the correct host or to another router in complex

networks.

Routers are also called Gateways, since they link multiple networks together. This is one of the parameters

that each device on the LAN needs to know. When a DHCP server is used it sets this address automatically.

In our network the Gateway address is the broadband router. This is the gateway to other networks.

The name Internet is a contraction of Internetwork. The Internet is a network of networks.

6.8 Name Resolution

Entering long strings of numbers such as 192.168.0.3 is not very convenient. The Domain Name Service

(DNS) allows a name to be used instead of a number. When you enter a name into your web browser such

as http://www.yahoo.com the browser first checks to see if this is a name of a device on the LAN. If it is

not local the request is forwarded to a DNS server. Your ISP provides the first server in the chain. If it

doesn’t know the address the request is passed to other DNS servers until the number is found. Once the

system obtains the IP address it uses the address to connect to the remote host. DNS names are intended as

a convenience for humans, computer use IP addresses to communicate. DNS acts as a giant Internet

“White Pages.”

Computers on the LAN use a different name resolution mechanism. Names are broadcast using NetBIOS

over IP. This works well when on small LANs, it eliminates the need to use a local DNS server or other

name resolution technique.

6.9 Whois

Some times it is useful to look up the owner of a domain. The WHOIS database stores contact information

for each registered domain name.

6.10 Network Neighborhood – My Network Places

Windows network neighborhood allows one to browse networked computers. To show up in the

neighborhood each machine must be configured for file and print sharing, even if nothing is being shared.

The neighborhood is organized by workgroup name, in a small LAN all machines typically belong to a

single workgroup, like HomeLAN. At least one machine in each workgroup must be configured as the

Browse Master. Ideally this is a machine that is left on all the time. Browse Mastership is negotiated at

power up; in general it is a good idea to disable the Brows Master on the clients. If the Browse Master is

running on a client, the network neighborhood becomes unavailable when the client is turned off, until the

remaining machines arbitrate Browse Master ownership again.

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Multitech RF500S Uživatelský manuál Strana 25