Tuesday, 19 November 2013

Router Tips to Make Your Wireless Faster

Posted by gurpreet at 21:37 0 comments

The router is the technological workhorse of the modern home, bringing Internet to your many devices. A router’s wireless speed is usually a user’s main concern: Unlike wired networks, wireless networks seem to suffer interference from objects in our everyday lives--should the router be above the dryer, or below; next to the microwave, or above? Wireless speeds can also be affected by too many devices sharing the same access point as well. Your device is fighting for limited bandwidth.

Many basic ways to improve your Wi-Fi network are available, such as placing the router in the center of the area you want it to cover, keeping the router away from metal objects that could block the signal, or making sure there aren’t too many other radio-enabled devices broadcasting on a 2.4GHz signal (standard for most older routers). But other ways to improve your signal may be a little less apparent. Here are some of those tricks (feel free to add your own workarounds in the comments below).
Check Your Speed

Although most people can gauge if their home wireless is too slow or not, checking the speed of the connection will let you know for sure whether you’re within range of the speed promised by your provider. Downloading a lightweight piece of software like LAN Speed Test gives you upload and download speed numbers in megabits per second (mbps), which you can check against your ISP’s promised speed to see if your network is actually slow or if you just need to pay for faster service. You’ll probably need to run the test multiple times and at different times of the day to get a real sense of how fast your Wi-Fi is overall, as crowding on the 2.4GHz spectrum could cause slowdown during the busiest times of the day for Internet traffic.

Change the Channel

If your wireless is weaker than it should be, you can try manually adjusting the broadcast channel to find one with fewer wireless routers competing for space. If your router is relatively new and automatically chooses which channel to broadcast from, then you won’t get too much use out of pinning your wireless down to a single channel, but for older routers it’s worth looking into.

First you’ll want to go into the router’s graphical user interface (GUI), by typing the router/gateway address into the address bar in a browser window while your computer is connected to the router’s wired or wireless network. You can usually find the router’s address on the router itself, in the instruction manual, or online if all else fails. For example, if you have a D-Link router, you’ll type http://192.168.0.1; if you have a Linksys, you’d type http://192.168.1.1. The browser will prompt you to enter your user name and password.

The exact navigation through the GUI for each router is different, but once you find the router’s wireless options (usually under headings like “LAN” or “Network”), you should see a “wireless channel” option. In North America, you can broadcast from channels 1, 6, and 11. Try switching to one of those three channels that’s not currently in use and see if it speeds things up.

Add Some Hardware Changing the actual hardware that makes the wireless signal waft through your house is an easy way to strengthen a wireless signal throughout a larger area. While most routers come with omnidirectional antennae (meaning they broadcast signal in all directions), you can also invest in a single-directional antenna that should double the strength of your signal, but only in one direction. This is great if you must place your router by a wall, and you don’t want to waste resources transmitting half of the wireless signal through the wall or window. Single-directional antennae can cost anywhere from $20 to $120.

Wireless repeaters do a similar thing, basically just repeating the signal put out by your router and helping you cover more space with Wi-Fi. These also cost around $20 for a low-end repeater, but if you’re up for a little DIY you can make your own wireless repeater for free by uploading custom firmware from DD-WRT to an old router (step-by-step instructions here, and an explanation of DD-WRT below).

Another hardware-related change: if you have multiple rooms you need to cover with your signal, consider buying a hybrid Homeplug/ wireless router device. Homeplug technology uses the AV line in your house to transmit broadband signals to other rooms, and if you include a wireless router on the adapter, you’ll have a Wi-Fi signal right there in the room with you.
Check Who’s on Your Network
You never want to leave your wireless signal without at least some sort of protection, and it’s worth noting that there are different levels of security on every router. Again, you’ll want to go to your router’s GUI and check its wireless security settings. Often, there will be a drop-down or click-to-select menu to allow different levels of security. WEP is the weakest form, and is easily broken; WPA is much more secure; and while WPA2 is the most secure, it can sometimes be incompatible with older devices on your network, so WPA is probably the best bet if you’re not sure what you want.

Again, somewhere in your router’s configuration (under “wireless” or “status”) there should be a list of devices that connect to your system. Keep in mind that this list of devices will also include the laptops and smartphones of any guests who used your Wi-Fi recently, or any cameras, printers, or other Wi-Fi enabled devices that you might use around the house. If you’re unsure, you can match the Media Access Control (MAC) addresses listed on the router GUI with the MAC addresses of your various devices.

If you do find intruders, you could change your wireless password, or some routers will allow you limit the number of devices that can connect to your network. Of course, there are programs out there that will allow you to triangulate the location of the moochers based on network signals. While the legality (and sanity) of trying to track down people who are using your Internet is questionable (and not sanctioned by PCWorld) there would probably be nothing wrong with knocking on your downstairs neighbor’s door and politely asking them in person to get off your Wi-Fi. There is, of course, the famous “Upside-Down-ternet” gag, where you turn the Wi-Fi thief's browser pages upside down, or make their browser pages blurry, or replace them with kittens! While it sounds fun, it’s a pretty advanced trick, so the average user might want to switch to WPA security and password-protect the network instead.

Adult Site Blocking With Open DNS

OpenDNS can block phishing attacks and adult sites.

Many new routers come with parental control options built into the device’s features. If you have an old router, however, you can use a service like OpenDNS. When your browser receives the command to retrieve a URL, it must go through a DNS server, which will look up the site’s numeric IP address. OpenDNS uses it’s own DNS lookup technology to resolve your browser’s page, meaning it can often bring up a web page faster. But one of the big perks for parents is that it also can block phishing attacks and adult sites that might get your kids in trouble.

OpenDNS doesn’t even require that you subscribe with them (the free version is ad-supported). Simply go to your router’s GUI and switch from an auto-generated IP address to a static IP address; then in the fields for DNS (there are usually 2 to 4 spaces for you to add a DNS lookup number), enter OpenDNS’s look-up numbers, which you can find on the OpenDNS site. Doing this from the router, rather than just configuring OpenDNS on a specific computer, will protect all the computers connected to that router.

Install Updated or Custom Firmware If you have an older router, or the settings on your new router don’t offer all the functionality you’d like, try upgrading your router’s firmware. Often, your router manufacturer will have firmware updates that you can easily download from the manufacturer’s website. And if you really want to supercharge your router, you can even upload custom firmware provided by DD-WRT.

While a lot of newer routers offer out-of-the-box DD-WRT compatibility, you can check on the DD-WRT website to see if your older router is compatible with the custom firmware. Upgrading can mean better firewalls, the ability to designate how much bandwidth each device on your network gets, and even client isolation, so that wireless users can connect to the network without being able to see each other (an important part of hosting a public access point). Follow the directions on the site to flash your router with DD-WRT, and then use it to modify your router to fit your needs.

Hybrid Modems/Routers Aren’t Off Limits
If your Internet service provider requires that you install a hybrid modem/router, you can try adding another router onto the system to get different functionality.

When I moved into a new apartment recently, I decided to subscribe to AT&T Uverse, which uses fiberoptic cable to bring the Net to your computer. AT&T requires subscribers to use a hybrid router/modem, and in my case the company installed a 2Wire 3800HGV-B modem/router. The Wi-Fi was okay, but the device had an 802.11g wireless access point, and I wanted to try my newer TRENDnet TEW-691GR router, which had an 802.11n access point.

In order to broadcast wireless from the TRENDnet router, I modified the two routers to work with each other. First, I went to the 2Wire’s summary status page, and under “Internet Details” recorded the primary and secondary DNS numbers, and also the range of the IP addresses listed under “Private Network DHCP info”, which in this case happened to 192.168.1.64 - 192.168.1.254.

A TRENDnet router's settings page. (Click for larger image.)

Then I connected an ethernet cable to a LAN port on both the 2Wire modem/router and the TRENDnet router, connected the TRENDnet router to my computer with another ethernet cable, and entered the TRENDnet configuration page. I navigated to “network” and “WAN setting” (although with other routers you might just look for the option to change the connection type and the DNS server setting). I changed the connection type to “Static.” In the field for IP address, I entered a number within the range given above; in the “subnet mask” field, I entered 255.255.255.0; and in the “default gateway” field, I entered the original 2Wire router/modem’s gateway address, as found on the router itself. Then, under DNS Server Setting, I entered the primary and secondary server settings that I found in the 2Wire’s configuration page. I saved everything, then went back to the 2Wire device.

A settings page of a 2Wire modem/router for AT&T's U-verse service. (Click for larger image.)

In the 2Wire’s configuration page, I first went to “system info,” then “Event Notifications,” and checked “enable detection of router-behind-router conditions.” Then, I navigated to the “Broadband” tab and clicked “link configuration.” Under “add additional network,” I checked “enable” and gave the TRENDnet router’s address (which I had used earlier to enter the TRENDnet’s GUI ) and the subnet mask 255.255.255.0. Don’t forget to keep saving your settings.

With the TRENDnet router still connected by a LAN port to the 2wire’s LAN port, both devices should be on and giving a wireless signal. When you can connect to both wireless networks successfully (you may have to close out of your browsers or do a “power cycle” by turning both the routers on and off), then you can go into the 2Wire’s modem/router menu and disable the “wireless” tab.

At this point, no wireless signal is coming from the 2wire, and all of the wireless transmitted in my apartment is at 802.11n standards. This workaround seemed to make my wireless slightly faster, but more unreliable. The network connection would suddenly crash, but when it was up and stable I seemed to be able to download videos faster. I would recommend activities of this type for experimentation only, as I ultimately just went back to the more stable 2Wire wireless network.

Readmore...

Tips to Boost Wireless Speed, Range, and Reliability

Posted by gurpreet at 21:29 0 comments

Wireless internet is awesome…When it’s fast, reliable, and has wide coverage that is. When the signal keeps dropping or the speed is so slow you might as well be on dial-up, it’s another story. Frustrating might be a mild description of the emotions a cruddy wireless network can evoke.
Thankfully, there are a number of easy, and completely free, tricks to get your WiFi working like a champ. We wrote this guide so even those “technologically challenged” among us can run through it in a few minutes.
But, before you dive in, you will need to login to your router using a web browser. Lucky for you, we’ve got a simple guide called “How to Login to a Wireless Router” that will lead you through the process.
Once signed into the router, you might have to click around a little bit to find the settings we need to adjust. Generally, you are looking for some sort of “wireless settings” or “advanced wireless settings” page. Don’t be afraid to poke around a little bit. We’ll let you in on a little secret. The all-knowing and oft nerdy IT people actually aren’t all-knowing. Quite often they have no idea how to solve a problem. However, they are willing to click around until they find the setting they are looking for.
Most computer wary people just need a confidence boost. Need some help getting the gumption to tackle this task? No problem. Here’s 13 things to make your day better. Okay, now we’re ready to kick some wireless butt.
Note: This tutorial assumes you already have a wireless router setup and that the computer you are using is connected to that network (hardwired connected is preferable). It is also written specifically for 802.11B/G/N devices. All of the tips are also applicable to 802.11AC, but the instructions may be slightly different.

1. Optimize wireless router location

Probably the easiest and most important improvement you can make is physically moving your router. Try a centralized location in your home. If it’s a two story home with a basement, put the router in the middle of the home on the first floor. Keep it away from devices that can interfere with a wireless signal, like a microwave or cordless phone. Also keep it away from foundational walls and out of cabinets. Don’t shove it at the bottom of an AV rack stuffed with home theater equipment or in your utility room. Your ultimate goal is to maximize coverage in the home by keeping the router away from things that might block or otherwise interfere with the signal. Try out a few different locations and then walk around your home with a wireless device and see how the signal changes.
Each time you move the router, you will want to record what the signal strength is and perform a speed test. This allows you to be more precise and strategic about the process, particularly in later parts of this guide. You can test the signal strength simply by observing how many bars your device shows. For those wanting the most accurate results possible, consider downloading the program inSSIDer. It allows you to see the wireless channel and signal strength of all of the wireless networks within range.

2. Hard wire as much as possible

This is a pretty simple suggestion. The fewer devices on a wireless network, the faster the network is likely to run. Not to mention that a hardwired connection is faster and more reliable in the first place. This process may involve moving some of your equipment around so you can get an Ethernet cable to it from the router. If you know your way around CAT cabling, you might check to see if the phone lines in your home are wired using CAT 5 or CAT 6. If they are, you could use the phone cables throughout your home to hard wire devices (heck, even CAT 3 can be made to work). You might also consider using an Ethernet over powerline adapter explained in our article on how to add wireless to hardwired devices.

3. Disable old wireless protocols

Even though your fancy new router may be super-fast with 802.11n (or even 802.11ac), as soon as a device connects using an older protocol, say, 802.11g, the entire network slows down. The fix to this problem is to set the router to only broadcast newer wireless modes. For your reference, the speeds from slowest to fastest are: b, g, n, ac. Notice in the picture below that you can select which modes you want the router to work with.

Disable Old Wireless Modes

If all of the devices on your network support wireless n (802.11ac is faster, but most devices don’t support it yet), then select “802.11n only”. Unfortunately, this will kick any devices not compatible with wireless n off of the network. You can either:
A) stop using the older devices.
B) upgrade their wireless cards, if possible.
C) hardwire them to the router instead of connecting wirelessly.
D) select a mixed operation mode (like 802.11g + n), or E) purchase a dual band router.
Dual band routers are like having two routers built into one (close enough, anyway). They can broadcast two separate wireless networks simultaneously. This means that you could setup a wireless g network for you older devices, and a wireless n network for newer devices. This allows the older devices to connect to WiFi without slowing down newer devices. But don’t get too excited yet. Dual band routers operate by sending out the two wireless networks on different frequencies, one at 2.4Ghz, the other at 5Ghz. Many new wireless devices still do not work on a 5Ghz network, even if the device is 802.11n compatible. Additionally, 5Ghz wireless networks have poorer range than 2.4Ghz networks. You will want to do some research to find out which devices of yours actually support 5Ghz before investing in a dual band router. With that said, if you are planning on buying a new router anyway, go with a dual band router.

4. Use WPA2 security only

WEP encryption used to be the standard when it came to wireless security. However, now it’s not only a poor form of protection, but it can limit the speed of your network. The same goes for the more modern WPA standard. If possible, you should limit your router to only work with WPA2 encryption.

Wireless Encryption Settings

5. Change the wireless channel

You’re certainly not the only person on the block with wireless internet and routers only operate on a limited number of channels. Multiple routers operating on the same channel can cause all sorts of issues, including dropping a wireless signal all together.
First, go to an area you normally have wireless problems. If there aren’t any real problem areas, just move a few rooms away from the router. Before changing anything, test the signal strength and speed, like you did when determining the best location for the router. This gives us a baseline and allows us to gauge the effects of any change we make.

Wireless Channel Setting

Most routers set the channel to “auto” by default. Find the channel setting in the router menu, and select the lowest option (CH 1 for 2.4gHz networks), then go back and check the signal strength and speed again. Repeat this process with a few different channels. I typically only test the lowest, middle, and highest channels. Once you have found the channel that gives you the best performance, select it and save the settings.

6. Change channel width

As wireless protocols have advanced, one of the ways they have increased speed is by operating using wider wireless channels. Wireless n routers need to use a 40Mhz channel width in order to achieve maximum speed. Most routers come with 20MHz as the default width, this is in an attempt to avoid interference. So, there is a potential for this change to negatively affect some users. If you start to notice issues, switch back to a 20Mhz operation. Also note that this isn’t really for increasing how fast you browse the internet, this change is more likely to be evident when streaming/transferring files between devices on your network.
Simply find the “Channel Width” setting in your router’s setting and change it to “Auto 20/40MHz”.

Channel Width

7. Use your DIY skills

If all of the by-the-book solutions fail, then think outside the book (or box). One of the most common DIY methods for creating a killer wireless network is to upgrade the firmware of your router to a version that allows you to boost output. The most common router used for this in an older version of the Linksys WRT54G, and the firmware is called “Tomato”. Lifehacker actually has a pretty good tutorial on the entire process. Keep in mind that not all routers are compatible with alternate firmware.
A second DIY option is to modify the antennae on the router. This is most easily done on routers with visible external antennae. If the original antennae can be unscrewed, purchase larger antennae and install them in place of the default set. Another option is to cut up a pop can or aluminum foil and direct the antenna signal in one direction, much like a satellite dish.

Conclusion

Following these 7 steps should allow you to get the most out of your wireless network. In some cases, you will notice huge benefits. For other people, who already have a solid network or don’t perform any bandwidth intensive tasks, the benefits might be more subtle. Either way, these tips should be considered best practices for setting up any wireless network.

Readmore...

Wednesday, 13 November 2013

How to Portforward on Windows 7/8

Posted by gurpreet at 02:12 0 comments

Hey guys

I'm going to show you how to portforward on Windows 8 / 7

Ok lets start !

{You maybe have to wait until all the images load !}

1.

Click here to view the original image of 767x179px.

Click here to view the original image of 767x408px.

Click here to view the original image of 767x409px.

Click here to view the original image of 767x408px.

Click here to view the original image of 767x408px.

Click here to view the original image of 767x408px.

Save it and you are done !

Readmore...

Wireless Tutorial (CCNA)

Posted by gurpreet at 01:46 0 comments

In this article we will discuss about Wireless technologies mentioned in CCNA.
Wireless LAN (WLAN) is very popular nowadays. Maybe you have ever used some wireless applications on your laptop or cellphone. Wireless LANs enable users to communicate without the need of cable. Below is an example of a simple WLAN:

Each WLAN network needs a wireless Access Point (AP) to transmit and receive data from users. Unlike a wired network which operates at full-duplex (send and receive at the same time), a wireless network operates at half-duplex so sometimes an AP is referred as a Wireless Hub.

The major difference between wired LAN and WLAN is WLAN transmits data by radiating energy waves, called radio waves, instead of transmitting electrical signals over a cable.
Also, WLAN uses CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) instead of CSMA/CD for media access. WLAN can’t use CSMA/CD as a sending device can’t transmit and receive data at the same time. CSMA/CA operates as follows:
+ Listen to ensure the media is free. If it is free, set a random time before sending data
+ When the random time has passed, listen again. If the media is free, send the data. If not, set another random time again
+ Wait for an acknowledgment that data has been sent successfully
+ If no acknowledgment is received, resend the data

IEEE 802.11 standards:

Nowadays there are three organizations influencing WLAN standards. They are:
+ ITU-R: is responsible for allocation of the RF bands
+ IEEE: specifies how RF is modulated to transfer data
+ Wi-Fi Alliance: improves the interoperability of wireless products among vendors
But the most popular type of wireless LAN today is based on the IEEE 802.11 standard, which is known informally as Wi-Fi.
* 802.11a: operates in the 5.7 GHz ISM band. Maximum transmission speed is 54Mbps and approximate wireless range is 25-75 feet indoors.
* 802.11b: operates in the 2.4 GHz ISM band. Maximum transmission speed is 11Mbps and approximate wireless range is 100-200 feet indoors.
* 802/11g: operates in the 2.4 GHz ISM band. Maximum transmission speed is 54Mbps and approximate wireless range is 100-200 feet indoors.
ISM Band: The ISM (Industrial, Scientific and Medical) band, which is controlled by the FCC in the US, generally requires licensing for various spectrum use. To accommodate wireless LAN’s, the FCC has set aside bandwidth for unlicensed use including the 2.4Ghz spectrum where many WLAN products operate.
Wi-Fi: stands for Wireless Fidelity and is used to define any of the IEEE 802.11 wireless standards. The term Wi-Fi was created by the Wireless Ethernet Compatibility Alliance (WECA). Products certified as Wi-Fi compliant are interoperable with each other even if they are made by different manufacturers.
Access points can support several or all of the three most popular IEEE WLAN standards including 802.11a, 802.11b and 802.11g.

WLAN Modes:

WLAN has two basic modes of operation:
* Ad-hoc mode: In this mode devices send data directly to each other without an AP.

* Infrastructure mode: Connect to a wired LAN, supports two modes (service sets):
+ Basic Service Set (BSS): uses only a single AP to create a WLAN
+ Extended Service Set (ESS): uses more than one AP to create a WLAN, allows roaming in a larger area than a single AP. Usually there is an overlapped area between two APs to support roaming. The overlapped area should be more than 10% (from 10% to 15%) to allow users moving between two APs without losing their connections (called roaming). The two adjacent APs should use non-overlapping channels to avoid interference. The most popular non-overlapping channels are channels 1, 6 and 11 (will be explained later).

Roaming: The ability to use a wireless device and be able to move from one access point’s range to another without losing the connection.
When configuring ESS, each of the APs should be configured with the same Service Set Identifier (SSID) to support roaming function. SSID is the unique name shared among all devices on the same wireless network. In public places, SSID is set on the AP and broadcasts to all the wireless devices in range. SSIDs are case sensitive text strings and have a maximum length of 32 characters. SSID is also the minimum requirement for a WLAN to operate. In most Linksys APs (a product of Cisco), the default SSID is “linksys”.
In the next part we will discuss about Wireless Encoding, popular Wireless Security Standard and some sources of wireless interference.

Wireless Encoding

When a wireless device sends data, there are some ways to encode the radio signal including frequency, amplitude & phase.
Frequency Hopping Spread Spectrum(FHSS): uses all frequencies in the band, hopping to different ones after fixed time intervals. Of course the next frequency must be predetermined by the transmitter and receiver.

The main idea of this method is signals sent on different frequencies will be received at different levels of quality. By hopping to different frequencies, signals will be greatly improved the possibility that most of it will get through. For example, suppose there is another device using the 150-250 kHz range. If our device transmits in this range then the signals will be significantly interfered. By hopping at different frequencies, there is only a small interference while transmitting and it is acceptable.
Direct Sequence Spread Spectrum (DSSS): This method transmits the signal over a wider frequency band than required by multiplying the original user data with a pseudo random spreading code. The result is a wide-band signal which is very “durable” to noise. Even some bits in this signal are damaged during transmission, some statistical techniques can recover the original data without the need for retransmission.
Note: Spread spectrum here means the bandwidth used to transfer data is much wider than the bandwidth needs to transfer that data.
Traditional communication systems use narrowband signal to transfer data because the required bandwidth is minimum but the signal must have high power to cope with noise. Spread Spectrum does the opposite way when transmitting the signal with much lower power level (can transmit below the noise level) but with much wider bandwidth. Even if the noise affects some parts of the signal, the receiver can easily recover the original data with some algorithms.

Now you understand the basic concept of DSSS. Let’s discuss about the use of DSS in the 2.4 GHz unlicensed band.
The 2.4 GHz band has a bandwidth of 82 MHz, with a range from 2.402 GHz to 2.483 GHz. In the USA, this band has 11 different overlapping DSSS channels while in some other countries it can have up to 14 channels. Channels 1, 6 and 11 have least interference with each other so they are preferred over other channels.

Orthogonal Division Multiplexing (OFDM): encodes a single transmission into multiple sub-carriers to save bandwidth. OFDM selects channels that overlap but do not interfere with each other by selecting the frequencies of the subcarriers so that at each subcarrier frequency, all other subcarriers do not contribute to overall waveform.
In the picture below, notice that only the peaks of each subcarrier carry data. At the peak of each of the subcarriers, the other two subcarriers have zero amplitude.

Below is a summary of the encoding classes which are used popularly in WLAN.

Encoding	Used by
FHSS	The original 802.11 WLAN standards used FHSS, but the current standards (802.11a, 802.11b, and 802.11g) do not
DSSS	802.11b
OFDM	802.11a, 802.11g, 802.11n

WLAN Security Standards

Security is one of the most concerns of people deploying a WLAN so we should grasp them.
Wired Equivalent Privacy (WEP)
WEP is the original security protocol defined in the 802.11b standard so it is very weak comparing to newer security protocols nowadays.
WEP is based on the RC4 encryption algorithm, with a secret key of 40 bits or 104 bits being combined with a 24-bit Initialisation Vector (IV) to encrypt the data (so sometimes you will hear “64-bit” or “128-bit” WEP key). But RC4 in WEP has been found to have weak keys and can be cracked easily within minutes so it is not popular nowadays.
The weak points of WEP is the IV is too small and the secret key is static (the same key is used for both encryption and decryption in the whole communication and never expires).
Wi-Fi Protected Access (WPA)
In 2003, the Wi-Fi Alliance developed WPA to address WEP’s weaknesses. Perhaps one of the most important improvements of WPA is the Temporal Key Integrity Protocol (TKIP) encryption, which changes the encryption key dynamically for each data transmission. While still utilizing RC4 encryption, TKIP utilizes a temporal encryption key that is regularly renewed, making it more difficult for a key to be stolen. In addition, data integrity was improved through the use of the more robust hashing mechanism, the Michael Message Integrity Check (MMIC).
In general, WPA still uses RC4 encryption which is considered an insecure algorithm so many people viewed WPA as a temporary solution for a new security standard to be released (WPA2).
Wi-Fi Protected Access 2 (WPA2)
In 2004, the Wi-Fi Alliance updated the WPA specification by replacing the RC4 encryption algorithm with Advanced Encryption Standard-Counter with CBC-MAC (AES-CCMP), calling the new standard WPA2. AES is much stronger than the RC4 encryption but it requires modern hardware.

Standard	Key Distribution	Encryption
WEP	Static Pre-Shared	Weak
WPA	Dynamic	TKIP
WPA2	Both (Static & Dynamic)	AES

Wireless Interference

The 2.4 GHz & 5 GHz spectrum bands are unlicensed so many applications and devices operate on it, which cause interference. Below is a quick view of the devices operating in these bands:
+ Cordless phones: operate on 3 frequencies, 900 MHz, 2.4 GHz, and 5 GHz. As you can realize, 2.4 GHz and 5 GHz are the frequency bands of 802.11b/g and 802.11a wireless LANs.
Most of the cordless phones nowadays operate in 2.4 GHz band and they use frequency hopping spread spectrum (FHSS) technology. As explained above, FHSS uses all frequencies in the the entire 2.4 GHz spectrum while 802.11b/g uses DSSS which operates in about 1/3 of the 2.4 GHz band (1 channel) so the use of the cordless phones can cause significant interference to your WLAN.

An example of cordless phone

+ Bluetooth: same as cordless phone, Bluetooth devices also operate in the 2.4 GHz band with FHSS technology. Fortunately, Bluetooth does not cause as much trouble as cordless phone because it usually transfers data in a short time (for example you copy some files from your laptop to your cellphone via Bluetooth) within short range. Moreover, from version 1.2 Bluetooth defined the adaptive frequency hopping (AFH) algorithm. This algorithm allows Bluetooth devices to periodically listen and mark channels as good, bad, or unknown so it helps reduce the interference with our WLAN.
+ Microwaves (mostly from oven): do not transmit data but emit high RF power and heating energy. The magnetron tubes used in the microwave ovens radiate a continuous-wave-like at frequencies close to 2.45 GHz (the center burst frequency is around 2.45 – 2.46 GHz) so they can interfere with the WLAN.
+ Antenna: There are a number of 2.4 GHz antennas on the market today so they can interfere with your wireless network.
+ Metal materials or materials that conduct electricity deflect Wi-Fi signals and create blind spots in your coverage. Some of examples are metal siding and decorative metal plates.
+ Game controller, Digital Video Monitor, Wireless Video Camera, Wireless USB may also operate at 2.4 GHz and cause interference too.

Readmore...

Monday, 4 November 2013

How to Set up an FTP Server in Ubuntu Linux

Posted by gurpreet at 22:18 0 comments

Steps

1
Boot up Ubuntu Linux.
2
Go to Application, then select Accessories and chose Terminal
3
Enter the following command: “sudo apt-get install vsftpd” (without quotation marks). This will install the FTP server on your system. If you are logged in as the root user, the "sudo" command will not be necessary, since this command is used to give administrative privileges to the user. In this case, you will only need the command "apt-get install vsftpd".
4
Open the FTP server configuration file. To do so, go to Places and click on Computer.
5
In the file browser, click the “File System” icon.
6
Click on the “etc” folder.
7
Double-click the “vsftpd.conf” icon.
8
Alter anonymous access. Enter "anonymous_enable=YES" (without quotation marks) to allow anonymous FTP access. The hash (#) at the beginning of each line indicates that this line is commented out and will be ignored. To enable this line, you must remove the hash (#). The parameter "write_enable=YES" (without quotation marks) will allow changes to the filesystem, such as uploading.
9
Rename the FTP welcome banner. Uncomment it by removing the hash (#), and enter the welcome message. For this example it's "ftpd_banner=Welcome to FTP Server!" (without quotation marks).
10
Click on Save and close the file. (Note: You may need to login as root, then only you will be able to open file in edit mode or else the file will open in read-only mode)
11
To restart the FTP service, type the following command: “sudo /etc/init.d/vsftpd restart” (without quotation marks). Again, you will only need to use "sudo" if you are no logged as the root user.
12
Place files on the FTP server. To move files to the server, access the FTP Folder from the command in the image below.

Readmore...