What is a Network Topology ?

In communication networks, a topology is a usually schematic description of the arrangement of a network, including its nodes and connecting lines. There are two ways of defining network geometry: the physical topology and the logical (or signal) topology.

 The physical topology of a network is the actual geometric layout of workstations. There are several common physical topologies, as described below and as shown in the illustration.

BUS NETWORK TOPOLOGY:- 

Every workstation is connected to a main cable called the bus. Therefore, in effect, each workstation is directly connected to every other workstation in the network.

Star Network Topology :-

There is a central computer or server to which all the workstations are directly connected. Every workstation is indirectly connected to every other through the central computer.

Ring Network Topology  :-

The workstations are connected in a closed loop configuration. Adjacent pairs of workstations are directly connected. Other pairs of workstations are indirectly connected, the data passing through one or more intermediate nodes.

Mesh Network Topology :-

Employs either of two schemes, called full mesh and partial mesh. In the full mesh topology, each workstation is connected directly to each of the others. In the partial mesh topology, some workstations are connected to all the others, and some are connected only to those other nodes with which they exchange the most data.

Tree Network Topology :-

Uses two or more star networks connected together. The central computers of the star networks are connected to a main bus. Thus, a tree network is a bus network of star networks.

Logical (Or Signal) Topology :- 

Refers to the nature of the paths the signals follow from node to node. In many instances, the logical topology is the same as the physical topology. But this is not always the case. For example, some networks are physically laid out in a star configuration, but they operate logically as bus or ring networks.

Hide folder or file with out any software

Password Protect folders in Windows without any Software

Most of us have private data. Not all of us have a private computer to keep that data. So, we just end up with other people viewing that data. Although password protecting software do work, it is almost useless to hide private data with these software(because we are always questioned as to what it is that we are hiding with the help of these software).

Hidden folders do not work as anyone can use Folder Options to make a hidden folder visible. So, we need an alternative way to create hidden password protected folders which only we can access. And that is exactly what we will learn in this post.

With this trick, you can create a secure password protected folder in Windows which no one except you can access. To use this trick, follow the instructions given below:-

1.  Open Notepad.

2.  Copy and paste the exact code given below:-

cls

@ECHO OFF

title www.tweakandtrick.com

if EXIST "Control Panel.{21EC2020-3AEA-1069-A2DD-08002B30309D}" goto UNLOCK

if NOT EXIST MyFolder goto MDMyFolder

:CONFIRM

echo Are you sure to lock this folder? (Y/N)

set/p "cho=>"

if %cho%==Y goto LOCK

if %cho%==y goto LOCK

if %cho%==n goto END

if %cho%==N goto END

echo Invalid choice.

goto CONFIRM

:LOCK

ren MyFolder "Control Panel.{21EC2020-3AEA-1069-A2DD-08002B30309D}"

attrib +h +s "Control Panel.{21EC2020-3AEA-1069-A2DD-08002B30309D}"

echo Folder locked

goto End

:UNLOCK

echo Enter password to Unlock Your Secure Folder

set/p "pass=>"

if NOT %pass%== computer goto FAIL

attrib -h -s "Control Panel.{21EC2020-3AEA-1069-A2DD-08002B30309D}"

ren "Control Panel.{21EC2020-3AEA-1069-A2DD-08002B30309D}" MyFolder

echo Folder Unlocked successfully

goto End

:FAIL

echo Invalid password

goto end

:MDMyFolder

md MyFolder

echo MyFolder created successfully

goto End

:End

3.  Click on the File Menu. Click on Save As.

4.  Select All Types in the Save As Type dropdown menu. Save the file as *.bat or Locker.bat.

After creating the file, double click on the Saved file. A new folder will be created. Enter your data in the folder. Again, double click on the batch file. Type Y and press Enter. The folder will be hidden from view.

To re-view your folder, double click on the saved batch file. Enter password as "computer" without quotes and press Enter key. This is also the default password. Your folder will be visible again.

To change the default password, edit the part of the code given in blue and enter your own password.

The overall usability of this trick can be improved by deleting the batch file after hiding your folder and re-creating it when you wish to access your folder again.

Note: This works on Windows 8, Windows 7, Windows XP and Vista. First try this on useless data to be sure and then only hide your personal data.

What is IP Address?

Internet Protocol Address (or IP Address) is an unique address that computing devices use to identify itself and communicate with other devices in the Internet Protocol network. Any device connected to the IP network must have an unique IP address within its network. An IP address is analogous to a street address or telephone number in that it is used to uniquely identify a network device to deliver mail message, or call ("view") a website. Dotted Decimals The traditional IP Addresses (IPv4) uses a 32-bit number to represent an IP address, and it defines both network and host address. Due to IPv4 addresses running out, a new version of the IP protocol (IPv6) has been invented to offer virtually limitless number of unique addresses. An IP address is written in "dotted decimal" notation, which is 4 sets of numbers separated by period each set representing 8-bit number ranging from (0-255).  An IPv4 address is divided into two parts: network and host address. The network address determines how many of the 32 bits are used for the network address, and remaining bits for the host address. The host address can further divided into subnetwork and host number. Class A, B, C and CIDR networks Traditionally IP network is classified as A, B or C network. The computers identified the class by the first 3 bits (A=000, B=100, C=110), while humans identify the class by first octet(8-bit) number. With scarcity of IP addresses, the class-based system has been replaced by Classless Inter-Domain Routing (CIDR) to more efficiently allocate IP addresses. Class Network Address Number of Hosts Netmask CIDR /4 240,435,456 240.0.0.0 CIDR /5 134,217,728 248.0.0.0 CIDR /6 67,108,864 252.0.0.0 CIDR /7 33,554,432 254.0.0.0 A /8 (1-126) 16,777,216 255.0.0.0 CIDR /9 8,388,608 255.128.0.0 CIDR /10 4,194,304 255.192.0.0 CIDR /11 2,097,152 255.224.0.0 CIDR /12 1,048,576 255.240.0.0 CIDR /13 524,288 255.248.0.0 CIDR /14 262,144 255.252.0.0 CIDR /15 131,072 255.254.0.0 B /16 (128-191) 65,534 255.255.0.0 CIDR /17 32,768 255.255.128.0 CIDR /18 16,384 255.255.192.0 CIDR /19 8,192 255.255.224.0 CIDR /20 4,096 255.255.240.0 CIDR /21 2,048 255.255.248.0 CIDR /22 1,024 255.255.252.0 CIDR /23 512 255.255.254.0 C /24 (192-223) 256 255.255.255.0 CIDR /25 128 255.255.255.128 CIDR /26 64 255.255.255.192 CIDR /27 32 255.255.255.224 CIDR /28 16 255.255.255.240 CIDR /29 8 255.255.255.248 CIDR /30 4 255.255.255.252 Note: (1) 127 Network Address reserved for loopback test. (2) Class D (224-247, Multicast) and Class E (248-255, Experimental) are not intended to be used in public operation. Public and Private IP Addresses In order to maintain uniqueness within global namespace, the IP addresses are publicly registered with the Network Information Center (NIC) to avoid address conflicts. Devices that need to be publicly identified such as web or mail servers must have a globally unique IP address, and they are assigned a public IP address. Devices that do not require public access may be assigned a private IP address, and make it uniquely identifiable within one organization. For example, a network printer may be assigned a private IP address to prevent the world from printing from it. To allow organizations to freely assign private IP addresses, the NIC has reserved certain address blocks for private use. A private network is a network that uses RFC 1918 IP address space. The following IP blocks are reserved for private IP addresses. Class Starting IP Address Ending IP Address A 10.0.0.0 10.255.255.255 B 172.16.0.0 172.31.255.255 C 192.168.0.0 192.168.255.255 In addition to above classful private addresses, 169.254.0.0 through 169.254.255.255 addresses are reserved for Zeroconf (or APIPA, Automatic Private IP Addressing) to automatically create the usable IP network without configuration. What is loopback IP address? The loopback IP address is the address used to access itself. The IPv4 designated 127.0.0.1 as the loopback address with the 255.0.0.0 subnet mask. A loopback interface is also known as a virtual IP, which does not associate with hardware interface. On Linux systems, the loopback interface is commonly called lo or lo0. The corresponding hostname for this interface is called localhost. The loopback address is used to test network software without physically installing a Network Interface Card (NIC), and without having to physically connect the machine to a TCP/IP network. A good example of this is to access the web server running on itself by using http://127.0.0.1 or http://localhost.