Practical Uses of Netstat Command in Analyzing Connected Foreign Addresses

Netstat command is a DOS command used to find all active TCP connections between your computer and other network devices with port numbers and TCP connection state. By simply using this command on command prompt, you will get the list of active TCP connections between local IP address(your computer) and foreign IP addresses. You can also find the port numbers open in those connections. With proper syntax we can effectively use it to view how your computer is connected to foreign computers. It has many important uses in computer security. Check the image below to understand its simple use.
proper use

List of Common Netstat Command Syntax
  1. netstat -n : Displays addresses and port numbers in numerical form

  2. netstat -a : Displays all connections and listening ports

  3. netstat -b : Displays the executable involved in creating each connections or listening ports.

  4. netstat -e : Displays Ethernet statistics

  5. netstat -o : Displays the Process Identifier associated with each connection

  6. netstat -p :Shows connections for the specific protocol only

  7. netstat r : Displays the routing table

  8. netstat s : Displays per-protocol statistics

Practical Uses of Netstat Command

If you are working on computer security, it is very handy. There are many practical uses like finding any programs established a connection to Internet without your knowledge, finding the IP address of a chat friend while sharing a file etc. Let us check some of such uses.

  1. Check Programs Established Connections

    It is important to find the names of applications installed on your computer established connection between your computer and a foreign address. Use the following format to find every applications having an active TCP connection.

    netstat -b
    code to find active internet programs

    You must need to run Command Prompt in administrator mode to execute this command. To learn how to do this, visit the link below.
    The Requested Operation Requires Elevation (Run as Administrator)

  2. Find Process Identifiers

    With netstat -o command you can find active TCP connections made on your computer with exact Process Identifiers(PID).
    Practical uses

  3. Find Absolute Domain name of Foreign Host

    One of the important application is to find the absolute domain name or Fully Qualified domain Name(FQDN) of the connected foreign address. It will give you a clear picture of the Internet foreign hosts who are connected to your computer. The syntax to find Fully Qualified domain Name of foreign address is given below.

    netstat -f
    Find FQDN of foreign connections

  4. Find the Offload

    We can find the current offload state of TCP connections using it. The syntax to find current TCP chimney offload state is give below.

    netstat -t
    important uses

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Tracert- Tool to Find the Path of a Packet

Tracert command is used to determine the path from your computer to destination host by sending ICMP Echo Request messages. The path though which the packet traveled will be printed in the command prompt. ICMP command Tracert is very helpful to troubleshoot any kind of network related issues. It is used to determine the network location where the actual cause of the issue present in any kind of network related issues. It sends ICMP Echo messages to the destination host and decrement its TTL value by one when it pass on hop. When the packets pass each hop it display the path in DOS window and you can easily identify the route. This feature helps to identify the actual cause of any network issue. So it is a handy tool for every network Engineers to analyze and troubleshoot network issues. Let us check how to use this tool.

If you want to know the route of the server of from your computer, you can check it by typing following code on DOS prompt.


We use Tracert command to find out the path taken to deliver the packets to the destination host from the source. Now let us check the general syntax of tracert command.

The general syntax is :
tracert [-d] [-h MaximumHops] [-j HostList] [-w Timeout] [TargetName]

Eg: tracert -h 30 After pressing enter we will a complete trace of the packet sent. The route is expressed in terms of hops. If there is a connection issues, it will show request timed out when the packet reaches the hop which is down.

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Uses of Netstat Command

Create Or Delete Windows User Account From Command Prompt

You can create a user account on your computer directly from Command Prompt by using the DOS command Net User. This command not only helps to create a new user account on a Windows computer but also helps to modify existing user account. This tutorial explains the use of the command net user and explains the procedure to create a new user account on a Windows computer. We also check how to modify an existing user account on a Windows computer using net user command.

Learn The Command Net user

Net user command is used to create, delete and edit user accounts on Windows computers from command prompt. Let us check different syntax to create, modify and delete user accounts from Command Prompt.

  • To create User Account:   net user Username Password /domain

  • To modify User Account:   net user Username Password /add /domain

  • To Delete User Account:   net user Username /delete /domain

While entering username from Command Prompt for a new user account, make sure it is maximum 20 character long. While typing password for the new account, you can use maximum 127 characters.

How to Fetch Admin Account Details From Command Prompt

Another practical use of net user command is to fetch the full information about administrator account on your Windows computer from command prompt. See how I used the net user command to get necessary details about the administrator account from Command Prompt.
Net User command

From this Command Prompt snap, you can see important information like the date on which the user account created, user's country code, the last date on which the password is set and the date on which the current password expires etc. You can also see the last date on which the account is accessed by a user and if there any logon restriction is created, it too will be listed.

Windows Tutorials
  1. How to Unlock Secret Windows Administrator Account

  2. How to use Netstat Command On Your Computer

  3. How to Bypass Windows Admin Account Password

  4. How to Disable USB Ports On a Computer

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Wireless Range Expander- an introduction

The function of a wireless range expanter is to extend the
range of the wireless signal from a wireless router....

The pictorial representation of the working is given below.

Wireless router--------(45 feet)----------------pc

Let us think the range of the router signal is 45 feet.
The wireless adapter on the pc will receive the signal
from the router and will create a connection
between the wireless router and the pc.

If the distance between the pc and wireless router is
70 feet what can we do?

Ans. Establish a range expaner in between the router and the pc.

The range expander will receive signal from the wireless router
and extend the signal to a certain limit.

wireless router-----(40 feet)------range extender----(30 feet)------pc( wireless

Now the wireless computer will go online by receiving signal from range expander.

Detailed explanation will be in the following posts......
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Session layer and Its Importance in OSI Reference Model

Session layer is the fifth layer in OSI reference model. It responds to service requests from Presentation layer and issues service requests to Transport layer. The major function of the Session layer is to create, maintain and terminate sessions. Session layer is also responsible for finding and sending data across correct connection. To setup and tear down connection Session layer communicate with Transport layer. Major functions of Session layer are listed below.

The major functions of session layer are:

  1. Starts and ends a session across a network
  2. Allows applications to share information.
  3. Ensures that information is flowing to the right place
  4. Communicate to presentation layer and Transport layer.

We can have multiple sessions on a network due to Session layer.

Eg: We are seeing a movie where sound and the seen both should match. It is one of the application of the Session layer. A list of protocols working in Session layer are listed below.

Major Session layer protocols

  1. AppleTalk Data Stream Protocol (ADSP)
  2. AppleTalk Session Protocol (ASP)
  3. Call Control Protocol for Multimedia Communication
  4. Internet Storage Name Service
  5. Network Basic Input Output (NetBIOS)
  6. Password Authentication Protocol (PAP)
  7. Point-to-Point Tunneling Protocol (PPTP)
  8. Remote Procedure Call Protocol (RPC)
  9. Short Message Peer-to-Peer (SMPP)
  10. Secure Shell (SSH)

Suggested Readings
  1. Physical layer

  2. Data link layer

  3. Network layer

  4. Transport layer

  5. Session layer

  6. Presentation layer

  7. Application layer

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Role of Transport Layer - Responsibilities and Protocols

Transport layer is the fourth layer in OSI Reference Model. It responds to service requests from Session layer and issues service requests to Network layer. Transport Layer is responsible for delivering messages between hosts. In Transport layer, data travels in the form of segments. Transport layer is responsible for creating an end to end connection between source IP and the destination IP. For establishing this end to end connection, Transport layer is using two major protocols TCP and UDP. TCP is connection oriented protocol where UDP is connection less protocol. So by using TCP we can create an end to end reliable connection between source and destination hosts. Transport layer is called host-to-host transport layer in TCP/IP model.

Duties of Transport layer

Major duties of Transport layer are:
  1. Creating an end-to-end connection between hosts in different network,
  2. Error recovery,
  3. Flow control,
  4. Ensuring complete data transfer in TCP
  5. Congestion avoidance

The end to end connection is established in Transport layer with the help of stateful protocol TCP. It offers reliable delivery of data to the destination host. Transport Layer is also responsible for error recovery and is responsible for the resending of data segments which had error. This feature is provided by TCP. Flow control is the process of ensuring where the amount of data sending to the destination is affordable by it. Without flow control a faster source might flood destination with so much information. To accomplish it we are using many techniques like windowing.

Major Transport Layer protocols

1. TCP( Transmission Control Protocol)

2. UDP( User Datagram Protocol)

3. DCCP (Datagram Congestion Control Protocol)

4. SCTP (Stream Control Transmission Protocol).

Suggested Readings
  1. Physical layer

  2. Data link layer

  3. Network layer

  4. Transport layer

  5. Session layer

  6. Presentation layer

  7. Application layer

MAC Sublayer Defined in IEEE 802.3

During the development of IEEE Ethernet, IEEE divided Data Link layer in to two. They are MAC sub layer and LLC sub layer. MAC sublayer functions are performed in hardware and is the bottom part of data link layer. MAC sublayer is defined in IEEE 802.3. MAC sublayer defines how data is transmitted in an Ethernet environment and defines framing, MAC addressing etc. Let us check the functions of MAC sublayer in details below.

Major Functions of MAC Sublayer in IEEE Ethernet
  1. Defines how information is transmitted in an Ethernet environment

  2. MAC Sublayer defines framing

  3. This Sublayer defines the working of Ethernet and MAC addressing

  4. CSMA/CD works in MAC Sublayer

How to Differentiate Ethernet II and MAC Sublayer Frames

We know Ethernet has two versions and it is important to know how to differentiate both versions of Ethernet. Major difference between Ethernet II (developed by DIX) and IEEE 802.2/3 is the frame value. If the frame value is greater than 1500, the frame is of Ethernet II. IEEE version of Ethernet use frames with value less than 1500. DIX version of Ethernet (Ethernet 2) does not have sub layers for data link layer. To read more about LLC Sublayer, visit the link below.
LLC Sublayer (IEEE 802.2 )

Without studying OSI Reference Model, you cannot start computer networking. To read about OSI Reference Model and its seven layered structure, visit the link below.
OSI Reference Model

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