IT-Hub

Difference Between Classful and Classless Subnetting

Classful IP addressing follows the default subnet masks assigned to each IP class. In this method, the network is not further subnetted, and the default mask of the class is used.

Examples of Classful IP addresses:

10.64.3.51
Subnet Mask: 255.0.0.0 (/8)

172.18.91.33
Subnet Mask: 255.255.0.0 (/16)

Classless addressing (CIDR – Classless Inter-Domain Routing) allows networks to be subnetted using different prefix lengths, instead of relying on the default class masks. This provides more flexibility and efficient use of IP addresses.

Examples of Classless IP addresses:

10.3.5.23/12

172.18.91.33/18

In classless addressing, the /number indicates the prefix length, which defines how many bits are used for the network portion of the IP address.

10.64.3.51

IP subnetting.

Subnetting means keep the network.
Suppernetting means Keep the host.

Telnet:

Uses TCP port 23.
Designed for remote terminal access without encryption.

SSH:

Uses TCP port 22.
Designed for secure remote login and command ex*****on.

Here’s a clear comparison between Telnet and SSH.

Telnet:

Transmits data (including usernames and passwords) in plain text.
Highly insecure and vulnerable to eavesdropping and attacks.

SSH (Secure Shell):

Encrypts all communication, including authentication and data transfer.
Provides strong security against interception and man-in-the-middle attacks.

Comparison of OSI and TCP/IP Models
- OSI has 7 layers; TCP/IP has 4 layers.
- OSI is a theoretical model; TCP/IP is practical and widely used.
- OSI separates presentation and session layers; TCP/IP combines them into the application
layer.

An IP address is a unique identifier for a device on a network.
IPv4: 32-bit address (e.g., 192.168.1.1)
IPv6: 128-bit address (e.g., 2001:0db8:85a3::8a2e:0370:7334)
Types of IP addresses:
- Public IP: Used on the internet.
- Private IP: Used within local networks (e.g., 192.168.x.x)

Common network devices include:
- Router: Connects different networks and routes data.
- Switch: Connects devices within the same network and forwards data intelligently.
- Hub: Broadcasts data to all devices; less efficient than a switch.
- Access Point: Provides wireless access to a wired network.
- Firewall: Monitors and controls incoming and outgoing network traffic based on security rules.

TCP/IP Model
The TCP/IP model is a more practical model used in real-world networking:
1. Network Interface ? Corresponds to OSI?s Physical and Data Link layers.
2. Internet ? Maps to OSI?s Network layer (e.g., IP).
3. Transport ? Same as OSI?s Transport layer (e.g., TCP, UDP).
4. Application ? Combines OSI?s Session, Presentation, and Application layers.

OSI Model (Open Systems Interconnection)
The OSI model is a conceptual framework used to understand network interactions in seven
layers:
1. Physical ? Transmits raw bit stream over the physical medium.
2. Data Link ? Handles error detection and correction from the physical layer.
3. Network ? Determines how data is sent to the receiving device (routing).
4. Transport ? Ensures complete data transfer (TCP/UDP).
5. Session ? Manages sessions between applications.
6. Presentation ? Translates data between the application and network format.
7. Application ? Closest to the end user (e.g., HTTP, FTP).

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Spanning Tree Protocol (STP)
همدا پروتوکول په Layer 2 Devices کې کار کوې لکه بریج او سويچ ، IEEE 802.1D پوری ارتباط لری.
په ساده ډول به ووایم وظیفه یی دا ده چې په یو نیټ ورک کې د Loop مخه نیسی Loop بیا د Redundancy په صورت کې رامنځته کیږي. Redundancy مطلب له یو څخه زیاتی لاری د معلوماتو د لیږلو لپاره درلودلو ته Redundancy وایي.

دکمپیوټر د ژبې ډولونه:
دکمپيوټر ژبې ډېر ډولونه لري چې مشهورې يې په لاندې ډول دي.
اول. Programming Language : دغه ژبې د کمپیوټر د پروګرام د جوړلو او ډیزاین کولو لپاره استفاده کیږي او یا هغه ژبې دي چې به مرسته يې کولای شو کمپيوټر ته یوه ځانګړې لارښوونه وکړو. لکه C #, C++, JAVA, C او داسې نور.

دوهم. Scripting Language : دا هغه ژبې دي چې د Scripting لپاره استعمالیږي لکه :Python, Type Script, JavaScriptاو داسې نور.

دریم . Query Language یا د ډيټابېس ژبې: هغه ژبې دي چې دډيټا د ساتلو لپاره او به هغه باندې نورو عملیو لکه: تغير راوستل او بېرته تر لاسه کول لپاره استعمالیږي لکه: SQL, MY SQL او داسې نور.