Windows XP has a built-in feature (shutdown tools) that is used to shutdown any connected computers from any one computer. Using this feature, you can log off, restart and shutdown any computer in your network. This tip is very useful for you, if you are a Network Administrator at your company, because if you have experience to shutdown all connected computers daily in your local area network one by one, definitely that job is annoying responsibility for you. Follow the given steps to configure shutdown tool on your computer: To use this feature, you will need to be logged into your computer with administrative rights. To perform this task, first make sure your both computers are directly connected or connected to network. Click Start button then type shutdown -i in Run option then press Enter for next. A small windows dialog box will appear with the title "Remote Shutdown Dialog". Here first click on "Add" button to add computer, a small Add computers window will open, here type the name or IP address of the computer (you can add many computer for same action) that you want to turned off, then press OK for next. Now select the action "What do you want these computers to do (log off, restart or shutdown)". If you want to warn your users about this action, select the check box "Warn users of the action" then set time, display warning for 30 seconds or more. Now select the option that describes the reason to shutdown the computers and also type some comments for users. Now when you press the OK button, the users will see a "System Shutdown Windows "with time and comments that you had been set.
How to log off, restart and shutdown, connected computer from one location?
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OSPF Neighbor States
| OSPF neighbors go through states before they can begin exchanging LSAs. You can examine the state of an OSPF neighbor with the help of following command:- A#show ip ospf neighbor a. DOWN STATE This state occurs when configuration is mismatched on both sides e.g. If STUB is configured on one side only. STUB is one of the fields in HELLO packet. HELLO packet contains following information/fields:- The Router-ID of the originating router. The Area-ID of the originating router interface. The address mask of the originating interface. Authentication type and authentication information for the originating interface. The Hello Interval of the originating interface. The Router Dead Interval of the originating interface. The router priority. The Designated Router (DR) and Backup Designated Router (BDR) information. Five flags for options. The Router-ID of the originating router's neighbors. This is the initial state of the neighbor which also indicates that no hellos were heard from this neighbor within the last dead time interval. b. INIT OR ONE WAY STATE One router (A) sent Hello packet to other router (B) and the information is matched on the other router (B). In response other router (B) sent acknowledgment, but it is in the pipeline. This state indicates that a router has seen its own Router-ID in the neighbor field of the HELLO packet that it received from the neighbor. It also means that bidirectional conversation was established and that DR and BDR election can occur. c. TWO WAY STATE Router-A sent HELLO Packet and Router-B sent acknowledgment, after that, Router-B sent Hello packet and Router-A sent acknowledgment in response. Then neighbor table is completed and DR/BDR Election process begins. When an OSPF interface first becomes active, it begins to send hello packets. When two routers receive each other's hello, they place the neighbor in INIT STATUS. When a neighbor is in init status, it places its own Router-ID into the hello packet. When a router receives one of the new hellos with the Router-ID of its neighbor, it places the neighbor in a new state of 2-WAY. The 2-Way state ensures that here is a two-way communication between the routers. The routers must be in this state before they can negotiate a DR/BDR and exchange LSAs. After the routers have achieved the 2-Way state, OSPF enters into its final states: d. EXSTART (MASTER/SLAVE) A simple meaning of this state is "who will initialize the communication first". At this state, another election for the selection of Master and Slave Router begins. The neighbor with the highest IP address becomes the Master and other becomes the Slave to exchange LSA. e. EXCHANGE (LSA REQUEST) The router sends its database description packets to neighbors in the exchange state. The database description packets describe the entire link state database. The link-state database is synchronized after this phase. After synchronization, the router enters one of two final states. Every network in the routing table of a router has a corresponding sequence number. At this state, a router sends the sequence numbers to the neighbor router. In response, as acknowledgment, the neighbor router also sends its sequence numbers. f. LOADING The router also sends link state request packets to all neighbors that are in the loading state. The loading phase requests that more recent LSAs be sent. At this state the database table is completed. g. FULL At this state, SPF algorithm is applied and best path is calculated. Neighbors in this state are fully adjacent and routing table of neighbors are completed.
Break or recover the router password
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Turn the power switch off and back on to recycle the power.
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Press the Break key or key sequence to put the router into ROM Monitor mode. The break key varies by computer or terminal software. The sequence might be CTRL-D, CTRL-Break or another combination.
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At the > prompt, type 0 to record the current value of the configuration register normally 0x2102, or 0x102.
>o
Configuration register = 0x2102 at last boot
Bit# Configuration register option settings:
15 Diagnostic mode disabled.
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Type o/r 0x2142 to tell the router to boot from flash without loading the configuration in NVRAM at the next reload.
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Type i to have the router reboot. The router ignores the configuration in NVRAM.
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The router runs the setup dialog, Type no or press Ctrl-C to skip the initial setup Dialog.
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Type enable ate the Router> prompt to go to privileged exec mode.
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Copy the startup configuration to the running configuration by using the configure memory or copy startup-config running-config commands. Do not type configure terminal. If you use the configure terminal command, you overwrite the configuration stored in NVRAM.
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View the configuration by typing write terminal or show running-config. View the configured line, vty and enable passwords. Any encrypted passwords need to be changed.
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Enter the configuration mode by typing configure terminal. Change the line of enable passwords as necessary.
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All interfaces are in a shutdown state. Issue the no shutdown command on every interface that is to be used.
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Type config-register 0x2102 to return the router to normal operation at the next reloads.
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Exit configuration mode by pressing Ctrl-Z
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Save your changes by typing write memory or copy running-config startup-config.
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Reload the router and verify the passwords.
Most commonly used Security Techniques against viruses.
|Virus detection and its removal are mode through an antivirus or with some other security program. Different antivirus programs are available in the market and over Internet. The most common and famous security technique against viruses is as under:
Virus Signature/ Virus Definition
Virus signature is a known pattern of code of a code of a virus program; this pattern is used by antivirus program to detect viruses and then to remove these viruses. You should update virus definition continuously by downloading updates from Internet. This ensures that your antivirus is always able to detect changing viruses.
Inoculation
Inoculation file is separate file created and maintained by antivirus program to record information like file size and file creation date. This information later on is used for virus detection and removal.
Quarantine
Quarantine is a separate area on a hard disk. It contains the infected files and folders that cannot be cleared or deleted by antivirus due to some reason, for example sharing violation or unknown virus for that antivirus.
Recovery Disk
Recovery disk is a removable disk that holds un-infected system commands and startup information. In case the boot record of actual hard disk fails, this recovery disk can be used to start the computer. Afterwards an antivirus program can be used to remove the virus.
Un-authorized access
Accessing a computer system without the knowledge or permission of its user is called unauthorized access. It is always recommended to restrict computer resources with the help of usernames and passwords. These are unique combination of characters to identify users and their secret codes respectively.
Firewall
Firewall is a security system consisting of hardware and software to prevent unauthorized access of a network or computer. Big companies use a separate computer firewall software or hardware to protect their date from unauthorized access. Firewall check outgoing and incoming traffic and manage data access to the authorized users only.
Biometric Devices
A biometric device reads personal characteristics like fingerprints hand structure, facial features, and voice recognition to authenticate a user for any further access to a computer system or other peripheral devices. A biometric device translates the personal characteristics into digital code that is matched to already store user data in that system. If the digital data matches with any of the stored data, it gives access to the person. In case of no match, the access is denied.
How to set auto shutdown for your computer?
| A cool tip to manage your computer shutdown process automatically. You can set your computer to shutting down at any convenient time (daily, weekly and when my computer starts) when you are not there. A simple shutdown command set your computer to close all running applications and shutdown properly after predefined time. This tip is very useful to save energy and time. After the execution of command, a small window will appear to count time of system shutdown. You can cancel this auto shutdown process using same command. Follow the given steps to schedule the shut down process: Click on start button then go to Run option. Type shutdown.exe -s -t yyyy then press ok button. Here yyyy mean time in second, for example if you want your computer will shutdown automatically after 5 minute then the command will be shutdown -s -t 300. But after execution you can cancel this command any time, simple type shutdown.exe -a in Run option and Press ok. Your auto shutdown command will remove and your computer will work properly.
