User Datagram Protocol - UDP
UDP is an unreliable, connectionless protocol

The udp means userdatagram protocol. In udp we cannot expect
the authentication. Authentication means we can get back an
acknowledge. In tcp we can expect aUthentication. But not in
udp. It is a unreliable protocol.

defualt gateway is address of router and router is use to 
connect two or more ip addresses

default  gate way is  simply that  we can say that address  
of same that   router and modem    provide the connectivity 
between dns server and main   server.

10 m/c can work together in workgroup network.

Hay we can use n no of computers in workgroup, but we can,t 
share resource more than 10 systems.

In wndows OS we can connected minimum 2 Machines & maximum 
10 M/C in a Workgroup.

In windows OS support minimun 2 pc , maximun 50 pc able to 
connected single workgroup

application layer  is    seventh layer of 0si model.
Provide  the  interface to  software..  like all kinds of 
application software.
protocls works on   application  layar are 
http,ftp,udp,dhcp,telentetc..

application layer is then seventh layer of the open system 
interconnection.it is the layer which is closely related 
with the user. user can run any application program. the 
proto col that works on application layer are ftp(file 
transfer protocol)used for transfering files,telnet for 
remote access,dhcp(dynamic host configration protocol)used 
for assigining ip address automatically,http(hyper text 
transfer protocol) ,and udp(user data granm protocol)

In the Open Systems Interconnection (OSI) communications 
model, the application layer provides services for an 
application program to ensure that effective communication 
with another application program in a network is possible. 
The application layer is not the application itself that is 
doing the communication. It is a service layer that 
provides these services:

It may be cause of Memmory or Hard disk to Read the Data

you must having Administrative privilledge, use Run :- 
gpedit.msc command

verfy syvol folder or verfy  log file (.log )

when active is installed you can see these in admin tools

Active directory users and computers
Active directory sites and services
Active directory Domain and trusts
Domain controller security policy
Domain security policy

See the AD Content in ADMINISTRATOR TOOL

users and computers
sites and services
Domain and trusts
DC security policy
Domain security policy

Run--->"DSA.MSC". if you are getting "Active directory 
users and computers window......

using dcpromo it can be identified

NAT is Network address Translation ( ip address translate 
from local ip to global ip and vice versa)

PAT is Port address translation ( port are translate from 
local to global ip's ) like on port 8080 web service port 
80 will work on PAT . it more over NAT only.

ccna more important why because in all over the world 73% of
the companies using cisco devices.and they r easy to
configure and maintainance.ccna deals with switches and
vlans for the cisco devices.it is an entry level exam of cisco.

ccna more important why because in all over the world 73% 
of the companies using cisco devices.and they r easy to 
configure and maintainance.ccna deals with awitches and 
vlans for the cisco devices. it is an entry level exam of 
cisco.

ccna because it covers all router and baisc topics

First of all you should know from inside you which path you 
like to select as Sys Admin or Network Admin it is 
depending on you
I would like to tell you something , if you want to make 
your carrier with strong Knowledge & Base ,I suggest you go 
for MCP and clear two Paper 1.Network infrastructure 
administration & planning, 2.ISA 2004 or any latest you 
like , it will give you the basic knowledge regarding 
internet world, network & security and then prepare for 
CCNA Exam, in those two paper most of cover the point to 
Prepare/give CCNA Exam.
Remember “Aim Your Target & Achieve Goal , for achieving 
goal you should have plan”
From my side I thought for your carrier on this way MCP>CCNA
(This two certification should not take more than 4 month 
to complete and then go for CCNP>CCIE
Be a All-rounder
Best of Luck