Saturday, 24 March 2012

Strategies for Maximizing the Life of Your Hard Drive

If I asked you the question: which part of your computer is the most fragile, what would you say? What if I asked: which part is most important to you?
Often, the answer to both of these questions is your Hard Drive.


Your hard drive is likely one the most important things you own. It contains work data, school data, emails, photos, music, movies, tax information, etc… Incidentally, the hard drive is also one of only two moving components in your computer (the other being your optical drive). The following is a list of important maintenance and monitoring techniques you can use to maximize the life of your hard drive and prevent data loss.



Hard drives are physically fragile – handle with care
Statistics show that 25% of lost data is due to a failure of a portable drive. (Source: 2001 Cost of Downtime Survey Results)
Contrary to its seemingly rugged appearance, your hard disk is a very delicate device that writes and reads data using microscopic magnetic particles. Any vibration, shock, and other careless operation may damage your drive and cause or contribute to the possibility of a failure. This is especially relevant for notebook users, as they are most at risk of drive failure due to physical damage, theft, and other causes beyond their control. That’s why we recommend regular backup of notebook hard drives, as often as possible.
Possible solutions include external USB or Firewire drives (although these are prone to the same risks), desktop synchronization, or backup at a data center through the web.



Hard drives write data in a non-linear way forcing it to become fragmented.


When files accumulate on your hard drive, they do not just get written in a linear fashion. A hard drive writes files in small pieces and scatters them over the surface. The fuller your hard drive becomes and the more files you save and delete the worse file fragmentation can be. Hard drive access times increase with fragmentation since your drive must work harder to find all the pieces of the files. The more fragmented your data is, the harder the actuator arm has to work to find each piece of a file.

A case in point: Disk fragmentation is a common problem for users of Outlook Express and database software. Each time outlook saves new mail, it does so in a different physical location from the previous time. This results in extreme fragmentation, causing longer hard drive access times and forcing more strain on the heads. This strain can eventually lead to a head crash, and often that means a virtually unrecoverable drive.Finally, in the event of a total crash, a fragmented drive is much more difficult to recover then a healthy defraged drive.

Luckily, Windows makes it remarkably easy to defrag your hard drive, simply launch the Disk Defragmenter utility (Start > Programs > Accessories > System Tools), choose which disk or partition you’d like to defragment and set it to work overnight or while you are not actively using your computer. Defragmentation will speed up your computer and ensure a longer life for your hard drive.



A very small power surge can fry a hard drive – use a UPS and turn off your computer when you can

Another little-known fact about the fragility of your hard drive is its susceptibility to electrical failure. An electrical failure can be caused by a power surge, lightening strikes, power brown-outs, incorrect wiring, a faulty or old power supply, and many other factors. If a power surge enters your computer, it may do an unpredictable amount of damage, including destroying your hard drive’s electronics or crashing the heads and possibly resulting in total data loss.
The best way to protect your computer from such dangers is to use a highly rated protected power bar or an Uninterruptible Power Supply (UPS). Although these devices won’t eliminate the chances of a crash, they will serve as effective protection in most cases. Also, you can minimize the danger of an electrical problem and reduce wear of your hard drive by turning off your computer or using power-save modes whenever possible. It’s a known fact that 100% of drives fail, the question is when will it happen and will you be prepared? Make sure to check out the knowledgebase section of our website for more detailed information on how electrical power affects your computer.



Be SMART, monitor the health of your drive to prevent unexpected crashes

All modern hard drives have a self-monitoring technology called SMART (Self Monitoring Analysis & Reporting Technology). What most people don’t realize is that the majority of hard drive failures do not have to be unexpected. Most failures occur as a result of long-term problems which can be predicted. By regularly monitoring disk health and performance, you can know about potential hard drive problems before you lose any of your data.

Several excellent utilities are available, including DiskView and Stellar SMART for standard IDE and SATA desktop drives. Also available are tools that monitor the health of SCSI drives and full RAID Array systems. Ariolic Software offers a great utility called ActiveSMART.



The only fool-proof way to prevent data loss is... Backup!

If you only take one of the suggestions here to heart, let it be this one: always back up your important data. After all the monitoring and all the prevention measures are in place, one fact still remains: all hard drives fail. Backing up regularly will ensure that you’re never caught without your critical data. For individuals, the simplest solutions include external portable hard drives, dvd’s, and online storage. For businesses, we recommend renting space at a secure data centre and implementing a disaster recovery plan, regardless of the size of your business.

I hope that the above techniques give you some idea of the importance of hard drive maintenance and provide some insights in how you can protect yourself from data loss.

Friday, 23 March 2012

How to Configure Router

Cisco Router Configuration Tutorial
Cisco Inter-network Operating System:
Cisco IOS Modes of Operation
The Cisco IOS software provides access to several different command modes. Each command mode provides a different group of related commands.
For security purposes, the Cisco IOS software provides two levels of access to commands: user and privileged. The unprivileged user mode is called user EXEC mode. The privileged mode is called privileged EXEC mode and requires a password. The commands available in user EXEC mode are a subset of the commands available in privileged EXEC mode.
The following table describes some of the most commonly used modes, how to enter the modes, and the resulting prompts. The prompt helps you identify which mode you are in and, therefore, which commands are available to you
Mode of Operation
Usage
How to Enter the Mode
Prompt
User EXEC
Change terminal settings on a temporary basis, perform basic tests, and list system information.
First level accessed.
Router>
Privileged EXEC
System administration, set operating parameters.
From user EXEC mode, enter enable password command
Router#
Global Config
Modify configuration that affect the system as a whole.
From privileged EXEC, enter configure terminal.
Router(config)#
Interface Config
Modify the operation of an interface.
From global mode, enter interface type number.
Router(config-if)#
Setup
Create the initial configuration.
From privileged EXEC mode, enter command setup.
Prompted dialog
User EXEC Mode:
When you are connected to the router, you are started in user EXEC mode. The user EXEC commands are a subset of the privileged EXEC commands.
Privileged EXEC Mode:
Privileged commands include the following:
• Configure – Changes the software configuration.
• Debug – Display process and hardware event messages.
• Setup – Enter configuration information at the prompts.
Enter the command disable to exit from the privileged EXEC mode and return to user EXEC mode.
Configuration Mode
Configuration mode has a set of submodes that you use for modifying interface settings, routing protocol settings, line settings, and so forth. Use caution with configuration mode because all changes you enter take effect immediately.
To enter configuration mode, enter the command configure terminal and exit by pressing Ctrl-Z.
Note:
Almost every configuration command also has a no form. In general, use the no form to disable a feature or function. Use the command without the keyword no to re-enable a disabled feature or to enable a feature that is disabled by default. For example, IP routing is enabled by default. To disable IP routing, enter the no ip routing command and enter ip routing to re-enable it.
Getting Help
In any command mode, you can get a list of available commands by entering a question mark (?).
Router>?
To obtain a list of commands that begin with a particular character sequence, type in those characters followed immediately by the question mark (?).
Router#co?
configure connect copy
To list keywords or arguments, enter a question mark in place of a keyword or argument. Include a space before the question mark.
Router#configure ?
memory Configure from NV memory
network Configure from a TFTP network host
terminal Configure from the terminal
You can also abbreviate commands and keywords by entering just enough characters to make the command unique from other commands. For example, you can abbreviate the show command to sh.
Configuration Files
Any time you make changes to the router configuration, you must save the changes to memory because if you do not they will be lost if there is a system reload or power outage. There are two types of configuration files: the running (current operating) configuration and the startup configuration.
Use the following privileged mode commands to work with configuration files.
• configure terminal – modify the running configuration manually from the terminal.
• show running-config – display the running configuration.
• show startup-config – display the startup configuration.
• copy running-config startup-config – copy the running configuration to the startup configuration.
• copy startup-config running-config – copy the startup configuration to the running configuration.
• erase startup-config – erase the startup-configuration in NVRAM.
• copy tftp running-config – load a configuration file stored on a Trivial File Transfer Protocol (TFTP) server into the running configuration.
• copy running-config tftp – store the running configuration on a TFTP server.
IP Address Configuration
Take the following steps to configure the IP address of an interface.
Step 1: Enter privileged EXEC mode:
Router>enable password
Step 2: Enter the configure terminal command to enter global configuration mode.
Router#config terminal
Step 3: Enter the interface type slot/port (for Cisco 7000 series) or interface type port (for Cisco 2500 series) to enter the interface configuration mode.
Example:
Router (config)#interface ethernet 0/1
Step 4: Enter the IP address and subnet mask of the interface using the ip address ipaddress subnetmask command.
Example,
Router (config-if)#ip address 192.168.10.1 255.255.255.0
Step 5: Exit the configuration mode by pressing Ctrl-Z
Router(config-if)#[Ctrl-Z]
Routing Protocol Configuration
Routing Information Protocol (RIP)
Step 1: Enter privileged EXEC mode:
Router>enable password
Step 2: Enter the configure terminal command to enter global configuration mode.
Router#config terminal
Step 3: Enter the router rip command
Router(config)#router rip
Step 4: Add the network number to use RIP and repeat this step for all the numbers.
Router(config-router)#network network-number
Example: Router(config-router)#network 192.168.10.0
Note: To turn off RIP, use the no router rip command.
Router(config)#no router rip
Other useful commands
• Specify a RIP Version
By default, the software receives RIP version 1 and version 2 packets, but sends only version 1 packets. To control which RIP version an interface sends, use one of the following commands in interface configuration mode:
Command
Purpose
ip rip send version 1
Configure an interface to send only RIP version 1 packets.
ip rip send version 2
Configure an interface to send only RIP version 2 packets.
ip rip send version 1 2
Configure an interface to send only RIP version 1 and version 2 packets.
To control how packets received from an interface are processed, use one of the following commands:
Command
Purpose
ip rip receive version 1
Configure an interface to accept only RIP version 1 packets.
ip rip receive version 2
Configure an interface to accept only RIP version 2 packets
ip rip receive version 1 2
Configure an interface to accept only RIP version 1 or 2 packets.
• Enable or Disable Split Horizon
Use one of the following commands in interface configuration mode:
Command
Purpose
ip split-horizon
Enable split horizon.
no ip split-horizon
Disable split horizon.
Open Shortest Path First (OSPF)
Step 1: Enter privileged EXEC mode:
Router>enable password
Step 2: Enter the configure terminal command to enter global configuration mode.
Router#config terminal
Step 3: Enter the router ospf command and follow by the process-id.
Router(config)#router ospf process-id
Pick the process-id which is not being used. To determine what ids are being used, issue the show process command.
Router(config)#show process
Step 4: Add the network number, mask and area-id
Router(config-router)#network network-number mask area area-id
The network-number identifies the network using OSPF. The mask tells which bits to use from the network-number, and the area-id is used for determining areas in an OSPF configuration.
Example:
Router(config-router)#network 192.168.10.0 255.255.255.0 area 0.0.0.0
Repeat this step for all the network numbers.
To turn off OSPF, use the following command.
Router(config)#no router ospf process-id
Other useful commands
• Configure OSPF Interface Parameters
You are not required to alter any of these parameters, but some interface parameters must be consistent across all routers in an attached network.
In interface configuration mode, specify any of the following:
Command
Purpose
ip ospf cost cost
Explicitly specify the cost of sending a packet on an OSPF interface.
ip ospf retransmit-interval seconds
Specify the number of seconds between link state advertisement retransmissions for adjacencies belonging to an OSPF interface.
ip ospf transmit-delay seconds
Set the estimated number of seconds it takes to transmit a link state update packet on an OSPF interface.
ip ospf priority number
Set router priority to help determine the OSPF designated router for a network.
ip ospf hello-interval seconds
Specify the length of time, in seconds, between the hello packets that a router sends on an OSPF interface.
ip ospf dead-interval seconds
Set the number of seconds that a router’s hello packets must not have been seen before its neighbors declare the OSPF router down.
ip ospf authentication-key password
Assign a specific password to be used by neighboring OSPF routers on a network segment that is using OSPF’s simple password authentication.
Interior Gateway Routing Protocol (IGRP)
• Create the IGRP Routing Process
To create the IGRP routing process, use the following required commands starting in global configuration mode.
Step
Command
Purpose
1
router igrp autonomous-system
Enable an IGRP routing process, which place you in router configuration mode.
2
network network-number
Associate networks with an IGRP routing process.
• Disable Holddown
The holddown mechanism is used to help avoid routing loop in the network, but has the effect of increasing the topology convergence time.
To disable holddowns with IGRP, use the following command in router configuration mode. All devices in an IGRP autonomous system must be consistent in their use of holddowns.
Command
Purpose
No metric holddown
Disable the IGRP holddown period.
• Enforce a Maximum Network Diameter
Define a maximum diameter to the IGRP network. Routes whose hop counts exceed this diameter are not advertised. The default maximum diameter is 100 hops. The maximum diameter is 255 hops.
Use the following command in router configuration mode.
Command
Purpose
metric maximum-hops hops
Configure the maximum network diameter.
• To turn off IGRP, use the following command.
Router(config)#no router igrp autonomous-system
Border Gateway Protocol (BGP)
• Enable BGP Routing
Use the following commands in global configuration mode.
Step
Command
Purpose
1
router bgp autonomous-system
Enable a BGP routing process, which places you in router configuration mode.
2
network network-number [mask network-mask] [route-map route-map-name]
Flag a network as local to this autonomous system and enter it to the BGP table.
• Configure BGP Neighbors
BGP must completely understand the relationships it has with its neighbors.
Command
Purpose
neighbor {ip-address | peer-group-name} remote-as number
Specify a BGP neighbor.
• Reset BGP Connections
Use either of the following commands in EXEC mode to reset BGP connections
Command
Purpose
clear ip bgp address
Reset a particular BGP connection.
clear ip bgp *
Reset all BGP connections.
• To turn off BGP, use the following command.
Router(config)#no router bgp autonomous-system
How to read router/link status
Status of router and links can be easily determined by power LED of router and link LED of each interface (if any). However, you may find a transceiver connected to an AUI port looks like the following:
When this transceiver is correctly connected, the “POWER” LED should light. Similarly, the “LINK” and “POLARITY” LEDs should light when you inserted the cable into the RJ45 socket on the transceiver. (Note that to get this result; the other end of the cable should be connected to some other devices as well.) If these LEDs are not light, you probably have problems with the link (cable).

Wireless Router & Security: A Step-By-Step Guide

Setting up a wireless router is easy. Essentially you turn your cable or DSL modem off and your wireless router on. Then, you connect the router to the modem with a cable, and turn the modem back on. You are more or less done. The wireless network wizard on your computer will pick up the router and, if your ISP does not have any special requirements, away-you-go, you are on the Internet.

For ease of setup and configuration, manufacturers ship wireless routers with all security disabled. Therein lies the problem. If you do not take any further steps to secure your router, and a surprising number of people don’t, your network will be wide open to all passersby and strangers. It’s like you’ve hung out a sign, “The door is open. Please come in and help yourself.”

The problem is not that strangers will be able to use your router to access the Internet but that, without further protection, would-be intruders will be able monitor and sniff out information you send and receive on your network. Malicious intruders can even hop on to your internal network; access your hard drives; and, steal, edit, or delete files on your computer.

The good news is that it is relatively easy to secure your wireless router. Here are three basic steps you should take.

1. Password protect the access to your router’s internal configuration

To access your router’s internal setup, open a browser and enter the routers setup URL. The URL will be specified in the manual. The URLs for D-Link and Linksys routers, two major manufacturers of wireless routers, are http://192.168.0.1 and http://192.168.1.1, respectively.

For Linksys routers, leave the user name blank and type “admin” (without the quotes) in the password field and press enter. To change the password, simply click on the Password tab and enter your new password.

For other routers, please consult your manual. Alternately, you can search on the Internet with the term “default login for ”. Don’t be surprised to find quite a number of pages listing default login parameters for many different routers, even uncommon ones.

2. Change the default SSID (Service Set IDentifier)

The SSID is the name of a WLAN (Wireless Local Area Network). All wireless devices on a WLAN use SSIDs to communicate with each other.

Routers ship with standard default SSIDs. For example, the default SSID for Linksys routers is, not unsurprisingly, “Linksys”. As you can see, if you don’t change the default SSID of your router a would-be intruder armed with a few common SSIDs from major manufacturers will be able to find your wireless network quite easily.

To change the SSID, click on the Wireless tab. Look for an input item labeled SSID. It will be near the top. Enter a new name for network. Don’t use something like “My Network”. Use a name that is be hard to guess.

3. Disable SSID broadcast

Wireless enabled computers use network discovery software to automatically search for nearby SSIDs. Some of the more advanced software will query the SSIDs of nearby networks and even display their names. Therefore, changing the network name only helps partially to secure your network. To prevent your network name from being discovered, you must disable SSID broadcast.

In the same screen that you changed the name of your network, you will see options for SSID broadcast. Choose “Disable SSID” to make your network invisible. Now save all your settings and log out.

Since your wireless network is now invisible, you will have to configure your computers to connect to your wireless network using the new name. On Windows XP, start by clicking on the wireless icon in the Notification Area and proceed from there.

With these three steps, your network now has basic security. However, if you keep sensitive information on your computers, you may want to secure your wireless network even further. For example, you can

- Change the channel your router uses to transmit and receive data on a regularly basis.
- Restrict devices that can connect to the router by filtering out MAC (Media Access Control) addresses.
- Use encryption such as WEP and WPA.

As with most things in life, security is a trade off between cost (time, money, inconvenience) and benefit (ease of use). It is a personal decision you make. However for the majority of home uses, the three basic steps plus WEP/WPA encryption provides reasonably strong security.

Turning on encryption is a two-step process. First you configure your router to use encryption using an encryption key of your choice. And then, you configure your computer to use the encryption key. The actual process of configuring your router for encryption varies from router to router. Please consult the router’s manual.

There are even stronger methods for ensuring security. A strong and robust security method is RADIUS (Remote Authentication Dial In User Service). Using RADIUS requires additional hardware and software. However, there are companies that offer RADIUS security as a subscription based service. The fees are reasonable and dropping.

Therefore for example, if you run a business on your wireless network, have sensitive data on your computers such as credit card information, and have a number of users who access your network, you should consider using RADIUS. Since the service sector for RADIUS is dynamic and growing, a search on the Internet with terms like “RADIUS subscription” or “RADIUS service” is probably the best way to locate one.