Firewalls are of two types:
-Hardware Firewall
-Software Firewall.
Firewall in simple manner is bascially the utility to provide the security over the network. These are the security measures that prevents the network’s in and out traffic to pass through the specific Security filters so that the unwanted and unsecure data can be stopped from entering into the network..
further… as a security measure it also depends on the network designer and implementer that how to use a Firewall mean to say the security measures like how to present the content filtering and Url filtering which type of firewall should be used and where to put it..

A Protocol is basically set of rules designed and developed for the internetwork or can say intranetwork Communications. the need of TCP had been rised in early years when like.. IBM Mainframe were not able to Communicate with the Burroughs mainframe.. means if you wish to connect 2 or more computers they should be same with everything from manufacturer to designer and implementer…then TCP imerged as a solution-for-ever..
EARLIER it was NCP( Network Control Protocal) but later it refined into TCP( Transmission Control Protocol) and IP(Internet Protocol)on jan.1,1983..
Some General roles of TCP/IP are:
1. Independence from particular vendor or network.
2. very low data overhead
3. good failure recovery.
and if the thinghs are taken seprately.. then
TCP is bascially responsible for proper data transmission by assuring data integrity it is a connection oriented protocol that follows the under scenerio
1. Handshaking.
2. Packect Sequencing
3. Flow Control.
4. Error handling.
IP : Since the data to be sent must be put somewhere the IP works here .. the required data is packaged in an IP packet.

TCP (Transmission Control Protocol) is a set of rules (protocol) used along with the Internet Protocol (IP) to send data in the form of message units between computers over the Internet. While IP takes care of handling the actual delivery of the data, TCP takes care of keeping track of the individual units of data (called packets) that a message is divided into for efficient routing through the Internet.

You can change a mac address easly. go to the desktop>write click on the my computer icon>properties>device manager>Network Adapters> properties> advance>network address.. and then chnage the value. The value should be hexadecimal or 16 octat

Ping ia process which use ICMP protocl error message which is encapsulated in a IP packets its calculate the round trip delay time by sending the packet sending time and subtract it from arrival time. the error messages are 1.destination unrecheable.
Yes, we can connect two or more system using many types of mathodes..
1. Remote Help Invitations.. if you have high or medium speed internet connection you can access the system..
2. VPN.. using the Virtual Private Network this is technology which is use to make virtual network between any remote location. VPN make a tunnel type connection for fast & secure communication.
3. Using third party software we have many type of VPN softwares.

The User's compaining of delay are:
- get the user(s) to demonstrate the problem

- determine how many other users are affected

- ensure desktop hardware and configuration is OK

- trace all connections (they may be on another subnet)

- commence some monitoring or diagnostics

- determine problem (if there is one)

- provide solution

WDS stands for Wireless Distributed System, & work as Bridging Technology.
In WDS mode Access Point can communicate with Wi-Fi Access Points only does not support Wireless Cliens.

If we want communicate 4 AP to each other so we should configure one AP as WDS mode.

In this mode WSD AP requires Remote AP mac address so you have to type other APs MAC address one by one.

and Configure AP in AP with WDS mode with Remote WDS mac address..

with this setting u can make Wireless LAN with out any ethernet wire.

ISA is Software Firewal & Internet Soloution for small & large network. ISA server blocks Inboud traffic as well as Outbound traffic.
It is a multitasking firewall server it provides NAT (Natwork Address Translation)& Web Proxy etc..
ISA server provides SecureVPN for connect Remote Clients or Remote Location…

Domain is a Security boundery which is use to make secure or private network from inside to outsite. Domain provide better administration control over the network object.