Normal configuration parameters for a
workstation include: IP address and subnet mask, DNS setting, default
gateway and subnet mask, IP Proxy, WINS, DHCP, host name, and Internet
domain name.
IP Address and Subnet Mask
When assigning IP addresses, two
important factors must be considered: the IP address needs to be
unique and the IP address must be assigned a subnet mask. When a DHCP
server assigns an IP address, it specifically assigns unique addresses
to each device, not duplicating any address. If manually assigning IP
addresses, it is important no two devices have the same IP address.
Each address must also have a subnet
mask to properly communicate with the network. The network and host
ids of an IP address are determined by the subnet mask; therefore, it
is important that each IP address has a subnet mask.
DNS Setting
Domain Name Services (DNS) is a name
resolution service that resolves (associates) host names to IP
addresses. DNS keeps a record of IP addresses and hosts names in a
process called a domain. DNS provides services along a hierarchical
chain, with a database design similar to a file tree structure
(root-level/top-level/second-level/host name). DNS also services
requests for host names that can not be resolved locally. Large
internetworks have several levels of DNS servers to provide efficient
name resolution.
Default Gateway and Subnet Mask
The interface of a router, which
resides on a LAN, is called the default gateway. The default gateway
is the location where all non-local network traffic that has no
specific route to a destination is sent and the default gateway acts
as an entry and exit point of a subnetwork.
When sending data to a remote subnet,
the host sends the packet to the initial router specified as its
default gateway. The router receives the packet, then must determine
whether the destination location is on its
local networks or send the data to another router for delivery.
IP Proxy
A proxy server is a type of a
"go-between" between the Internet and the users of a
network. If a client needs information from the Internet, the proxy
server searches for the destination and retrieves the information.
This provides for higher security and faster service because the
client, itself, does not directly connect to the destination.
WINS
Windows Internet Naming Service (WINS)
works as DNS does to resolve IP addresses with host names. WINS uses a flat
namespace by using NetBEUI, instead of using a hierarchical one like DNS.
To resolve an
IP address, WINS client hosts registers its NetBIOS and IP addresses
with the WINS server, then the WINS client host sends a name query
request to the WINS server, indicating that it desires to transmit to
another host. If the desired IP address and host name are found in the
server's WINS registry, then they will be sent to original WINS client
host. Requests made by WINS are routable. The WINS proxy agent is used
for non-WINS clients such as UNIX hosts; however, WINS does not
provide support for Macintosh OS's.
DHCP
The Dynamic Host Configuration Protocol
(DHCP) automatically distributes IP address settings to devices, which
are connected to the network, when DHCP Server clients log on. When a client tries to
connect to network, a request is sent to the DHCP server for configuration settings.
Once the server receives the
message, the DHCP server sends a reply to the client, which includes
the configuration information, then keeps a record of the addresses
that have been assigned. DHCP uses the BOOTP protocol to communicate
with clients. Clients must renew their IP addresses after 50% of the
address lease life, and again at 87.5% of the lease life, by sending a
DHCPREQUEST message. Client hosts keep their IP address until their
lease expires or they send a DHCPRELEASE command. IPCONFIG and
WINIPCFG are utilities run from the command line that allow
verification of the IP Address information that has been assigned to
the client host.
Host Name
A host name is assigned by the network
administrator to identify each device on the network. By default, on
Windows-based machines, host names are the names of the computers.
Internet Domain Name
The Internet Domain Name is assigned by
ARIN, a company that assigns all the domain names on the Internet. The
domain name consists of two parts, the hostname and the domain. In the
address www.cisco.com, the www is the host name and the cisco.com is
the domain. Combined together, www.cisco.com becomes a fully qualified
domain name (FQDN).
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