Category: OS Windows and Tips Tricks

Basic simplified Computer Boot process

Today would like to share little, simplified information on Computer Boot process. Before we work on our computers and on GUI (Graphical User Interface) and when the computer is powered on the following series of pre-programmed actions takes place

World of Compters

  1. The BIOS (Basic Input/Output System) does a power –on Self-Test (Called as POST) and initiates the boot process
  2. The Boot-strap process locates the mater Boot Record (MBR) of the primary boot device (HardDisk, cd, floppy disk, USB) as determined by the BIOS
  3. The MBR of the bootable device points the boot –strap to the Boot Sector of the active Partition.
  4. The Boot-strap then loads the OS boot loader in to the computers main memory (RAM). At this point the role of the BIOS is completes and control is transferred to the OS.
  5. The OS boot loader then loads its various components in to the computers main memory completing the boot sequence and providing the user its user interface.


Netstat Command to troubleshoot port conflicts

Would you like to know network status on your computer? Or would you like to know what network communication threads are open between your computer and networked or remote computers, then

Netstat is the right dos command to use to find this information.

The netstat command is a Command Prompt command used to display very detailed information about how your computer is communicating with other computers or network devices.

Specifically, the netstat command can show details about individual network connections, overall and protocol-specific networking statistics, and much more, all of which could help troubleshoot certain kinds of networking issues or it will help you troubleshooting application communication issues. These commands also useful to find malicious traffic from external IPs and ports open.

Netstat Command Syntax:

netstat [-a] [-b] [-e] [-f] [-n] [-o] [-p protocol] [-r] [-s] [-t] [-x] [-y] [time_interval] [/?]

You can refer the following links to know more about these switches while using with the Netstat.

http://en.wikipedia.org/wiki/Transmission_Control_Protocol

http://pcsupport.about.com/od/commandlinereference/p/netstat-command.htm

There are many more information resources available on internet in order to understand the use of Netstat command.

One of the simplest way I use to find the current network connections and their status by running the following Netstat command and export the data in text file to ease my job.

Syntax:

Go to command prompt.

StartàRunàcmdàok

Under the commandline Window, Type

Netstat –anob>port.txt   and press Enter

Then type port.txt

It will open up the port.txt with information about Source IP/Destination IP and ports used.

For example, the above command should look like

C:Netstat –anob>port.txt

C:port.txt

When you open the text file, you will see TCP (Transmission control protocol) operations and its status. Refer the following table for most common TCP communication status

TCP connection State Represents
LISTEN (server) represents waiting for a connection request from any remote TCP and port.
SYN-SENT (client) represents waiting for a matching connection request after having sent a connection request
SYN-RECEIVED (server) represents waiting for a confirming connection request acknowledgment after having both received and sent a connection request
ESTABLISHED (both server and client) represents an open connection, data received can be delivered to the user. The normal state for the data transfer phase of the connection.
FIN-WAIT-1 (both server and client) represents waiting for a connection termination request from the remote TCP, or an acknowledgment of the connection termination request previously sent.
FIN-WAIT-2 (both server and client) represents waiting for a connection termination request from the remote TCP
CLOSE-WAIT (both server and client) represents waiting for a connection termination request from the local user.
CLOSING (both server and client) represents waiting for a connection termination request acknowledgment from the remote TCP
LAST-ACK (both server and client) represents waiting for an acknowledgment of the connection termination request previously sent to the remote TCP (which includes an acknowledgment of its connection termination request).
TIME-WAIT (either server or client) represents waiting for enough time to pass to be sure the remote TCP received the acknowledgment of its connection termination request. [According toRFC 793 a connection can stay in TIME-WAIT for a maximum of four minutes known as a MSL (maximum segment lifetime).
CLOSED (both server and client) represents no connection state at all.

 

Again this is just basic info on using the netstat command and not detailed information on how TCP/IP protocol communicates over the network. You can refer the above links or refer the below link for more detailed information.

http://en.wikipedia.org/wiki/Transmission_Control_Protocol

http://docs.oracle.com/cd/E19455-01/806-0916/6ja85399h/index.html

 

Hope the provided information above helps. If you know any additional information or simplest tips to use netstat command please do share with others by commenting on this blog.


Windows Tips: Using Safe Mode Options

Using Safe Mode Options

 

The various forms of Safe Mode—with networking, without networking, with command prompt—load a minimal version of Windows with only the drivers and files needed to support that minimal version (like NTOSKRNL). These tools can be handy when something is preventing your system from booting and you suspect an errant driver. Whichever mode you choose, during boot, Windows will display a list of all the drivers and services as they’re loading. When you log out, the machine will restart as usual.

 

Safe Mode
Safe Mode starts Windows with only the drivers and services required to boot the computer.

Safe Mode with Networking
Safe Mode with Networking is that includes network support. Use this version when you need network support and you’re sure that the network drivers are not causing any problems. When you boot the computer into Directory Services Restore Mode, it’s booting into Safe Mode with Networking.

Safe Mode with Command Prompt
When you boot to this option, you’ll see a list of the files that Win2k is loading, and then the graphical interface will appear, running in 640×480. However, rather than loading the Desktop,  Win2K will use the command prompt for its shell.

The Last Known Good ConfigurationFor example, if you load the wrong driver for your keyboard, then you can boot to the Last Known Good menu to unload that driver and tell Win2K to use the one you had been using.

 


Windows Tips: How to Back Up the Registry

How to Back Up the Registry

 

Before you edit the registry, export the keys in the registry that you plan to edit, or back up the whole registry. If a problem occurs, you can then follow the steps how-to restore the registry to its previous state.

How to Export Registry Keys

  • Click Start, and then click Run.
  • In the Open box, type regedit, and then click OK.
  • On the File menu, click Export.
  • In the Save in box, select the boxs at the bottom the bottom according to weather you want to export all or only selected branches of the registry.
  • Next select a location in which to save the backup .reg file. In the File name box, type a file name, and then click Save.How to Restore the Registry
  • To restore registry keys that you exported, double-click the .reg file that you saved.

 


How To Convert File System and Remove Default Admin$ Shares

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How To Convert File System, fat – fat32 to ntfs

open a dos prompt and give the command

convert d: /fs:ntfs

this command would convert your d: drive to ntfs.

if the system cannot lock the drive, you will be prompted to convert it during next reboot.

Normally you should select yes.

Conversion from fat/fat32 to ntfs is non-destructive, your data on the drive will NOT be lost.

Be aware that converting to ntfs will make that partition of your
drive unreadable under dos unless you have ntfs utilites to do so.

How To Remove The Default Admin$ Shares

By default Windows 2000, Windows XP and WinNT automatically setup hidden admin shares (admin$, c$ and d$), this registry key will disable these hidden shares.

System Key: [HKEY_LOCAL_MACHINE System CurrentControlSet Services LanmanServer Parameters]
Value Name: AutoShareWks
Data Type: REG_DWORD (DWORD Value)
Value Data: (0 = disable shares, 1 = enable)

This registry key actually stops the recreation of the shares, therefore it may be necessary to delete the shares through the drive properties also or you can also remove the shares through the Computer Management Console.

1. In Control Panel, double-click Administrative Tools, and then double-click Computer Management.

2. Click to expand Shared Folders, and then click Shares.

3. In the Shared Folder column, right-click the share you want to delete, click Stop sharing, and then click OK.
Note : To remove the admin share for only the current session use the second method (Computer Management console), if you want a permanent removal, add the AutoShareWks registry