What is Active Directory?

A central component of the Windows platform, Active Directory directory service provides the means to manage the identities and relationships that make up network environments. For example we can create, manage and administratoror users, computers and printers in the network from active directory.

What is a DOMAIN? What is the difference between a domain and a workgroup? 

Domain is created when we install Active Directory. It’s a security boundary which is used to manage computers inside the boundary. Domain can be used to centrally administor computers and we can govern them using common policies called group policies.
We can’t do the same with workgroup.

What is DNS? Why it is used? What is “forward lookup” and “reverse lookup” in DNS? What are A records and mx records? 
DNS is domain naming service and is used for resolving names to IP address and IP addresses to names. The computer understands only numbers while we can easily remember names. So to make it easier for us what we do is we assign names to computers and websites. When we use these names (Like the computer uses DNS to convert to IP address (number) and it executes our request.

Forward lookup: Converting names to IP address is called forward lookup.

Reverse lookup: Resolving IP address to names is called reverse lookup.

‘A’ record: Its called host record and it has the mapping of a name to IP address. This is the record in DNS with the help of which DNS can find out the IP address of a name.

‘MX’ Record: its called mail exchanger record. Its the record needed to locate the mail servers in the network. This record is also found in DNS.

What id DHCP? Why it is used? What are scopes and super scopes?  

DHCP:Dynamic host configuration protocol. Its used to allocate IP addresses to large number of PCs in a network environment. This makes the IP management very easy.

Scope: Scope contains IP address like subnet mask, gateway IP, DNS server IP and exclusion range which a client can use to communicate with the other PCs in the network.

Superscope: When we combine two or more scopes together its called super scope.

What is the difference between a normal LAN cable and cross cable? What could be the maximum length of the LAN cable? 
The way the paired wires are connected to the connector (RJ45) is different in cross cable and normal LAN cable.

The theoritical length is 100 meters but after 80 meters you may see drop in speed due to loss of signal.


What is IPCONFIG command? Why it is used?

IPCONFIG command is used to display the IP information assigned to a computer. Fromthe output we can find out the IP address, DNS IP address, gateway IP address assigned to that computer.

What is APIPA IP address? Or what IP address is assigned to the computer when the DHCP server is not available?
When DHCP server is not available the Windows client computer assignes an automatic IP address to itself so that it can communicate with the network cmputers. This ip address is called APIPA. ITs in the range of 169.254.X.X.

APIPA stands for Automatic private IP addressing. Its in the range of 169.254.X.X.

What is BSOD? What do you do when you get blue screen in a computer? How do you troubleshoot it?
BSOD stands for blue screen of Death. when there is a hardware or OS fault due to which the windows OS can run it give a blue screen with a code. Best way to resolve it is to boot the computer is “LAst known good configuration”. If this doesn’t work than boot the computer in safe mode. If it boots up than the problemis with one of the devices or drivers.

What is a router? Why we use it?

Router is a switch which uses routing protocols to process and send the traffic. It also receives the traffic and sends it across but it uses the routing protocols to do so.

What are manageable and non manageable switches?

Switches which can be administered are called manageable switches. For example we can create VLAN for on such switch. On no manageable switches we can’t do so.

What is the active directory database name and where it is located?
The active directory database name is NTDS.Dit and located in c:windows tds
What is the expansion if .Dit?
Dit-Directory Information Tree and scalable up to 70 TB.

What is Lightweight Directory Access Protocol?
LDAP a Network protocol designed to work on TCP/IP stacks to exact information from a hierarchical directory such as x.500 and useful for searching through data to find a particular piece of information.