Saturday, August 15, 2009

802.11b WLAN Waveguide Antennas Unidirectional & Omnidirectional High gain, Simple construction

Waveguides? Aren't they a bit complicated?

In a word, Yes! Microwave technology is pretty esoteric, and it used to be reserved for the "spooks" designing electronic warfare systems, radars, and the like.

But microwave equipment has been steadily penetrating into mainstream applications. Microwave ovens (operating at 2.4GHz) have already been with us for several decades. These have been joined by satellite dishes and LNBs operating at 10GHz and more recently, multichannel 2.4GHz cordless phones.

Microwave technology seems complex because we have left the boffins in charge for too long. Microwave text books have been written by academics who revel in every detailed equation. But you don't really need to know about Poynting vectors or Maxwell's equations to deploy a really effective Wireless LAN. Let me show you how simple it really is...

What is the 2.4GHz ISM Band?

Wireless networking systems using the 802.11b standard operate in the 2.4GHz ISM band. Other services, including microwave ovens, medical equipment, and cordless phones also operate in the ISM band. The IEEE 802.11b standard defines how WLAN networking will be configured, and how interference can be minimized from the other services operating at the same frequencies.

Channel IDUS/CanadaEuropeFranceSpainJapan
1 2412 2412 - -2412
2 2417 2417 - - 2417
3 2422 2422 - -2422
4 2427 2427 - -2427
5 2432 2432 - -2432
6 2437 2437 - - 2437
7 2442 2442 - - 2442
8 2447 2447 - -2447
9 2452 2452 - -2452
10 2457 2457 2457 24572457
11 2462 2462 24622462 2462
12 - 2467 2467 - 2467
13 - 2472 2472 - 2472
14 - - - -2484

A WLAN receiver can use any of these channels, and can automatically hop from channel to channel if interference is encountered. An 802.11b antenna for the US and Canada should radiate well between 2410 and 2460 MHz.

Slotted Waveguide Antennas

Unlike wideband antennas like the biquad, slotted waveguides are resonant antennas, and have a relatively narrow operating frequency range. The designs I am describing on this page have an adequate bandwidth for any WLAN, but they have been carefully designed and must be equally carefully constructed.

The major attraction of a slotted waveguide design is its simplicity. Once you have built the first one it is very simple to build many more.

The gain varies little across the 802.11b spectrum, dropping a little bit at the extreme ends.


16 slot unidirectional, center feed

How I Produced These Designs and Charts

These slotted waveguide designs are the result of lengthy simulation using Zeland Software's Fidelity and IE3D electromagnetic simulators. Fidelity is much better at modelling waveguide structures than my favorite simulator, NEC2, but it is quite an expensive package, with a long learning curve...

Simulation can give you much more information about the performance of a microwave antenna than you get from building it. This is because there are severe limitations in the accuracy of measurements at microwave frequencies. Simulation makes it easier to see subtle interdependencies that would be very difficult to measure. In this case, I used the simulation to tell me how the antennas should behave, and then verified the performance both in my lab and on my antenna 'test range'. The results were surprisingly accurate - and attest to the quality of the Zeland Fidelity software.

8 slot waveguide E field propogation

How a Waveguide Antenna Works

A waveguide is a very low loss transmission line. It allows us to propagate signals to a number of smaller antennas (slots). The signal is coupled into the waveguide with a simple coaxial probe, and as it travels along the guide it traverses the slots. Each of these slots allows a little of the energy to radiate. The slots are in a linear array pattern, and the total of all the radiated signals adds up to a very significant power gain over a small range of angles close to the horizon. In other words, the waveguide antenna transmits almost all of its energy at the horizon, usually exactly where we want it to go. Its exceptional directivity in the elevation plane gives it quite high power gain. Additionally, unlike vertical colinear antennas, the slotted waveguide transmits its energy using HORIZONTAL polarization, the best type for distance transmission.

At left we can see a graphical representation of the E field intensity shortly after starting excitation of an 8 slot waveguide. The slots are to the left of the image. The coaxial probe is at the lower end of the image, and the field can be seen to be clumped at maxima every half wavelength as they travel up the waveguide. The waveguide airspace takes up the middle 1/2 of the bluespace, the rest is air infront of (to the left) and behind (to the right) the antenna.

If you click here you can bring up a Windows Media Format Movie version. An MPEG-1 version is at this link. You can see the wave travelling up the waveguide from the probe. The intensity of the E field is given by the color. Here we have primarily blue colors, about -40dB on the final (red) intensity which is achieved once the resonance is fully excited. When the signal first gets to the top and starts reflecting back down the air column it is still green, about -30dB from its ultimate intensity. Reflections are also occuring from the plug at the bottom of the airspace, and the sum effect of all these, including continual drive from the coaxial probe, allows the intensity to build up through yellow and red (0db) signal levels. You can see the signal radiating out the slots at the left of the image. The radiation intensity is less at the top than at the bottom in an 8 slot design, it is hard to radiate perfectly with such a limited number of slots.



Unidirectional Waveguide Antennas

I am going to describe two unidirectional designs. The first has 8 slots and is about 30 inches long. The second has 16 slots and is about 5 feet long. Simple to construct, the 8-slot has been provided as a good starting point for an antenna novice. I built my 8 slot prototype using only hand tools.

Simple 8 slot Unidirectional

Azimuth (Fidelity simulation) for the 8 slot waveguide antenna
Fidelity simulation of the Elevation plots for 8 slot slotted waveguide


8 Slot Unidirectional, no wingsHigh 15db gain 8 slot waveguide


Performance 16 slot Unidirectional

16 slot unidirectional with offset feed - click to enlarge

16 slot unidirectional with offset feed - click to enlarge

16 slot unidirectional with offset feed

The 16 slot design has been made to radiate over a wider beamwidth by the addition of "wings" to each side of the guide, flush with the front (slotted) surface. It is, of necessity, higher Q, and the higher gain is obtained over a narrower bandwidth. They can be expanded aluminium or sheet, and should extend 9.6 inches beyond the sides of the guide. They act as a ground plane for the slots. Do not change this dimension, it is two electrical wavelengths.


Omnidirectional Slotted Waveguide Antennas

The slotted waveguide has achieved most of its success when used in an omnidirectional role. It is the simplest way to get a real 15dBi gain over 360 degrees of beamwidth.

Horizontal Polarization in a wide area network can often double the number of users that can interconnect without interference. When using horizontally polarized BiQuads, or Patch antennas (provided that they have been tested for good cross-polarization performance) at the client site, these omnis will be 20 dB stronger than the signal from a similar vertical collinear. Conversely, vertically polarized receiver antennas will prefer the vertically polarized colinear over the slotted waveguide by a similar amount. Transmission on an immediately adjacent channel, (say, channels 5 or 7), normally not permissible because of interference, is now possible. So a judicious intermingling of horizontally polarized clients can talk with a horizontal central station on the same or adjacent channels that other clients are using with vertical polarization.

To make the unidrectional antenna radiate over the entire 360 degrees of azimuth, a second set of slots are cut in the back face of the waveguide. When looking stright at the face of the waveguide you will be able to see straight through both slots.

Unfortunately, unless a lot of slots are used, the antenna becomes more like a bidirectional radiator, rather than an omnidirectional. This antenna was invented in the 40's, and as our simulation and measurement technologies have become more accurate it is apparent that the slotted waveguide designs we have used in the past are far from optimum. The most common defect is a 'tilt' in the radiation pattern at the extreme ends of the frequency range. This occurs when the wavelength of the signal travelling down the guide differs from the slot spacing.

My current favorite uses 32 slots to get 15dBi of gain, radiated in a uniformly omnidirectional manner. The large number of slots makes it easier to dissipate the energy from the waveguide. Like with the 16 slot unidirectional, two sets of "wings (one set at each slot surface) are required to get equal radiation of energy over a full 360 degrees. Note that a higher Q is necessary to get all the slots illuminated evenly.

32 slot with phase wings

32 slot with phase wings

32 slot with wings, gain vs frequency

Note that the gain vs frequency curve is peaked at 2440, and it radiates well over all 14 channels.



Highly Directional Slotted Waveguide Antennas

Sometimes it is useful to have a highly directional antenna. For example, when installing a point-to-point link between two buildings it is not desirable to have a wide angle of coverage. Any interference from other 802.11b devices (or microwave ovens) that are in the radiation zone will affect your link integrity.

The ideal antenna for such a situation is a dish, such such as the Primestar dish. When using my Biquad feed, it is possible to reject interference outside the dish's primary 5 degree cone by 30 dB or more.

16 slot unidirectional in vertical polarization mode

But, if a 16 slot waveguide antenna is turned to a horizontal position, parallel with the ground, it will radiate vertical polarization. Its directivity in this plane is extremely good. As you can see from the diagram to the left, most of the spurious lobes are more than 20 dB down from the main signal, and they are very narrow (click to enlarge the image). This performance is comparable with my commercial HP2419G Parabolic Grid Antenna...

So, if you don't have a dish handy, consider the possibility of using a pair of these slotted waveguides, parallel to the ground. They will work well. Very well...


Constructional Details for the 8 Slot Unidirectional Antenna

The base extrusion for all my slotted waveguides is 4 inch by 2 inch O.D. rectangular aluminum tubing with approx 1/8 inch thick walls. Inside dimensions are 3.756x1.756 inches (95.4mm x 44.6mm). These inside dimensions are critical, and must be within +- 0.040 inches or +-1mm if the antenna center frequency is to be +- 1 channel. I cut the end inserts from a 5/16 inch by 1 3/4 inch flat aluminum bar extrusion. There - those are the last dimensions I will give in inches, as millimetres are a much more accurate way to describe the dimensions for a microwave antenna. Waveguide antennas are fairly critical in their constructional dimensions, and are easiest to make with a CNC milling machine. I have computed these designs so that they would be easy to replicate, and if you are plus or minus 1 mm the design will work fine - but you must be careful. I used a jig, a hand operated DeWalt heavy duty cut-out tool, a 1/4 inch router bit, and lots of water to 'machine' my slots, and it worked fine (even if it was a little tedious).

"Please machine this slot to 59.417mm in length"

In the days before computing power was free, engineers spent their whole careers deriving formulae to try and describe the operation and design of Slotted Waveguides. You can find designs specified to 1 or 2 decimal places of a millimeter, but I have rounded everything off to the nearest millimeter. Since it was relatively easy for me to "build" structure after structure in the electromagnetic simulator, an understanding of the inter-dependance of each parameter came quite quickly. That understanding takes away the 'black magic' that used to be associated with design of these antenna systems.

Really folks - plus or minus 1 mm will not kill your antenna!

Coupling the Signal Into the Waveguide

As I said above, we are propagating the WLAN signal down a waveguide and then using it to excite a number of elemental radiators, or slots. The first task is to get the signal into the waveguide with a feed probe. Obtain a suitable N connector, for example, the one from Amphenol in Figure 2 of this catalog page. Take a piece of 20mmx40mm copper or brass shim, cut the red portion and form it into the shape of a cone. Solder it to the inner conductor of your Type N connector (see photo). Its length should be 20mm, its largest diameter about 15mm. When soldered to the N connector it should protrude exactly into the center of the waveguide and no further.

N connector with feedcone attached

Both ends of the waveguide need to be terminated for RF, and the easiest way I found to do this was to cut 3.75 inch pieces (darn - there are those inches again - I will be excommunicated from the microwave community at this rate...) of 5/16 by 1.75 aluminum bar stock. I do not recommend that you make the end plugs sloppily, but good electrical contact is not required.

Remember not to have any screws protruding into the waveguide for more than 1/8 inch, especially the screws holding down the N connector. They will affect performance. Cone fab cutout

For the 8+8 slot omnidirectional antenna:

The total length of air inside the 8+8 slot omnidirectional waveguide, from end to end, is 765mm. Mount the N connector in the center of the widest side, 27.5mm from one end (the 'base') of the airspace in the waveguide and offset 10 mm from the centre line of the face, in the direction as the offset of the first slot.. The wavelength of the radiation passing down the waveguide is longer than a wavelength in free air (it is 161mm in this design).



The first slot is centered 1.0 wavelength from the base, at a maximum of the H field in the waveguide. This length is 161mm from the base of the airspace. It is the H component of the field that induces the energy into the slots, and makes them radiate. Each slot is 59mm long, and extends outwards from the centerline for a width of 17mm. The waveguide excites each edge of the slot depending on its position across the wide surface of the guide. If it straddled the exact centre, each edge of the slot would be excited in anti-phase, and there would be no radiation. So we offset the edges of the slots, the more the offset the greater is the energy that is dissipated into each slot. The electrical length of each slot should be 59mm. Do not allow too much kerf at the ends (2 mm radius max). I recommend finishing the cut with a 1/8 inch router bit (or a file). Or you might use the 1/8 bit in a CNC machine to cut the entire rectangular outline. Remember, even though these slots are arranged vertically they radiate horizontal polarization.

For the 8+8 omnidirectional, slots 2 thru 8 are centered at distances of 241, 322, 403, 483, 564, 644 and 724mm from the base of the airspace, staggerred across the centerline. It doesn't matter which direction the first one is cut, but they must alternate. The end plate should create a 765 mm airspace. Looking straight on at the front of the guide you can see right through both the front and back slots.

For the 8 slot Unidirectional:

The total length of air inside the 8 slot unidirectional, from end to end, is 760mm. Mount the N connector in the center of the widest side, 25mm from the base of the airspace in the waveguide. The wavelength of the radiation passing down the waveguide is 160mm in this design. The first slot is centered 1.0 wavelength from the base, at a maximum of the H field in the waveguide. This length is 160mm from the base of the airspace. Each slot is 58mm long, and extends outwards from the centerline for a width of 20mm. The waveguide excites each edge of the slot depending on its position across the wide surface of the guide. If it straddled the exact centre, each edge of the slot would be excited in anti-phase, and there would be no radiation. So we offset the edges of the slots, the more the offset the greater is the energy that is dissipated into each slot. The electrical length of each slot should be 59mm. Do not allow too much kerf at the ends. Remember, even though these slots are arranged vertically they radiate horizontal polarization.

Slots 2 thru 8 are centered at distances of 240, 320, 400, 480, 560, 640 and 720mm from the base of the airspace, staggerred across the centerline. It doesn't matter which direction the first one is cut, but they must alternate. The end plate should be to create a 760mm airspace.


16 and 32 slot construction

Constructional Details for 16 and 16+16 Slot Design

The correct wavelength for these designs is 161mm. The gain for the 16 slot Unidirectional is 15dBi-17dBi, verified on my test range, across the whole band. On the range the 16 slotter gives slightly higher gain than my Hyperlink Technologies model 2419G Mesh Parabolic, which is "rated" at 19.1dBi gain.

The slot width for the 16 slotter is 15mm, for the 32 slotter is 12mm, otherwise the key dimensions are the same.

Both PDF and DXF versions of the drawings are available for download.
(Many thanks to Jeff LaPlante for doing all this hard work).
More information is available from Jeff LaPlante's Website


The ZIP of drawings for the 32 slot omni can be downloaded by clicking this link.


Designs for different size tubing:

The optimum design for a 16 slot unidirectional with Indian standard 95.24mm x 38.39mm x 3.18mm tubing gives a wavelength of 163mm. This means that the slots are centered at 163mm / 2 = 81.5mm intervals, rather than the 161mm basis which was used in the Autocad drawings. The N connector for the feed is spaced only 25mm from the base of the airspace, and offset 10mm to the left of the centerline of the guide's face. The length of the aircolumn will be 163 x 8.75 = 1426mm. The slot width for the 16 slotter stays the same at 15mm, and the slot length should be 58mm. For the 16+16 slot omni version use a slot width of 12mm.

The feed cone must not protrude more than halfway into the waveguide. With this tubing, the feed cone should not protrude more than 19mm into the tubing. Just use the same drawing as I have shown above, but make it from 17mm X 34mm shim rather than 20x40.

100mm x 50mm x 3mm Metric size tubing: use the same 161mm wavelength and dimensions as for the US designs, but offset the feed point 15mm from center line instead of 10mm to bring the resultant SWR closer to unity.


Tuning screws for tweaking the SWR

You don't have to use them, but, for perfectionists, two screws #10 in diameter are tapped into the waveguide. The first, at 70 mm from the base, the second at 90mm. These can be used to adjust the center frequency downwards from the 2440 nominal to about 2420. More important is the ability of the tuning screws to cancel some of the reactance of the antenna, and reduce the SWR. The smith chart at the right was computed for the 16 slot uni waveguide. and is plotted for a frequency range from 2410 to 2520 in 10MHz steps, without any tuning screw tweaks. Inserting the tuning screws can tune the waveguide to a lower center frequency, and keep the SWR less than 1.5:1 over the entire band.

Those of you who are setting up the CNC files to make more than one or two of these things for your local (non-commercial) FreeNet should email me and set up a tuning session so I can help you get them just right

.S11 for 16 slot unidirectional with offset feed


Weather and your Antenna

Use nylon, aluminum or stainless steel screws and fasteners, as suits your preference, not normal (corrosive) ones. Unless you use some low RF loss tape (like mylar or kapton) to cover the slots, bugs will make their homes in the structure and spin their webs across the slots. There are two approaches to this. Either you dont bother about it, and just hose the antenna clean every year or so, or you use, and regularly replace, the protective tape. One tip - there is relatively little RF energy reaching the end away from the base, and if you mount the antenna upside down you can actually cut holes in the end cap so as to let out water and bugs that might otherwise accumulate there. I have simulated that 4 one half inch diameter holes in each vertex of the far end plug do not affect performance in any measurable way. I also simulated the use of a 2.75 by 1.75 inch plug at the far end (with 1/2 inch gaps for cleaning) and found no noticeable degradation. I don't recommend that you encourage bugs to accumulate near the feed probe, however...

So happy WLANing, and please don't forget to email me with your experiences.


Source : http://trevormarshall.com/waveguides.htm

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Friday, August 14, 2009

How To Hack Isp To Use Internet For Free (tools and video tutorial)

Superscan

Superscan is a free connect-based port scanning software designed to detect open TCP and UDP ports on a target computer, determine which services are running on those ports, and run queries such as whois, ping, ICMP traceroute, and Hostname lookups.

Superscan 4, which is a completely-rewritten update to the other Superscan, features windows enumeration, which can list a variety of important information dealing with Microsoft Windows such as:

* NetBIOS information
* user and Group Accounts
* Network shares
* Trusted Domains
* Services - which are either running or stopped

Superscan is a tool used by both system administrators, crackers and script kiddies to evaluate a computer's security. System administrators can use it to test for possible unauthorized open ports on their computer networks, whereas crackers use it to scan for a potentially insecure port in order to gain illegal access to a system.

Superscan 4 is produced by the Foundstone, a division of McAfee.

Here are some of the new features in this version.

* Superior scanning speed
* Support for unlimited IP ranges
* Improved host detection using multiple ICMP methods
* TCP SYN scanning
* UDP scanning (two methods)
* IP address import supporting ranges and CIDR formats
* Simple HTML report generation
* Source port scanning
* Fast hostname resolving
* Extensive banner grabbing
* Massive built-in port list description database
* IP and port scan order randomization
* A selection of useful tools (ping, traceroute, Whois etc)
* Extensive Windows host enumeration capability


a-Change Mac Address 5.0

Change Mac Address in seconds! Scan Mac Address within any range of IP address. Exports the scanning results from a Mac Address Lookup list. Spoofing the Mac Address of your network card to any new Mac Address.
Wake on Lan. Win Ipconfig.Port Scan.
Scan any range of IP for the proper Mac Address.
Support changing Mac Address of any network cards under Windows NT/2000/XP/95/98/2003.
Support exporting scanning mac address results to txt file.

A-MAC Address Change is a lightweight, easy-use MAC Address scanning and changing software. Don't let its small size fool you! It's filled with features such as:

* It's shockingly easy to use — just a simple input and click, that's it!
* It can scan any range of IP for the proper MAC Address.
* It supports exporting results of your scan to a text file.
* It runs on all Windows™ operating systems.
* It supports any network cards under Windows Me/95/98/NT/2000/XP/2003/Vista.
* It supports changing back to its original physical address.
* It recommends the proper Ethernet network card.
* It displays the information of your computer.
* It automatically checks the legality of IP range.
* It supports changing MAC searching speed.

But what does all this mean to you? Simple...

* You don't blow your time calling the ISP vendor and ask them to update the registered MAC Address to match the new hardware. Some Cable Modem ISP's assign IP addresses base on the PC's MAC addresses. For whatever reason, if you need to swap 2 PC's regularly to connect to the cable modem, it would be a lot easier to spoof MAC Addresses rather than to change Network Interface Card (NIC).
* You can scan the MAC Address of destination computer.
* You can perform security checking on MAC Address based authentication and authorization systems
* You can build Stand-by (offline) systems with the EXACT same Computer Name, IP address, & MAC Address as the Primary Systems. If Stand-by systems should be put online, NO arp table refresh is necessary, which eliminates extra downtime.
* Test network management tools.
* Some software can ONLY be installed and run on the systems with pre-defined MAC address in the license file. Now you can install one of these applications to another system with a different NIC.
* Troubleshoot Network problems: ARP Tables, Routing, Switching, etc.

http://www.filefactory.com/file/b5b7...ee_-_Video_rar
http://www.filefactory.com/file/413dca/n/tools_rar
http://www.filefactory.com/file/f076...uperscan30_rar
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About DD-WRT

DD-WRT is a Linux based alternative OpenSource firmware suitable for a great variety of WLAN routers and embedded systems. The main emphasis lies on providing the easiest possible handling while at the same time supporting a great number of functionalities within the framework of the respective hardware platform used.

The graphical user interface is logically structured, and it is operated via a standard Web browser, so even non-technicians can configure the system in only a few simple steps.

Apart from the simple handling, speed and stability are also in the focus of our development work. Compared to the software preinstalled on many WLAN routers, DD-WRT allows a reliable operation with a clearly larger functionality that also fulfills the demands of professional deployment.

The huge user community gives support to DD-WRT developers and the users themselves in various ways. Thanks to this, potential flaws in the system can be detected very quickly and can thus be corrected without delay. DD-WRT users can find help and suggestions from other users in the user forums, and the Wiki containing further information and how-to guides is being expanded and maintained by the DD-WRT community as well.

For devices mainly used for private purposes, DD-WRT is freely available. Platforms used for commercial purposes require a paid license. Compared to the freely available version, the professional version also allows for configuration of the WLAN parameters, thus opening up the opportunity of creating e.g. reliable and powerful network infrastructures. Special demands can be fulfilled by specifically tailored versions of DD-WRT.

Main characteristics:

  • supports more than 200 different devices
  • comprehensive functionality
  • supports all current WLAN standards (802.11a/b/g/n*)
  • supports outdoor deployment*
  • supports enhanced frequencies *
  • VPN integration
  • supports various Hotspot systems
  • bandwidth management
  • multilingual user interface


DD-WRT is:

  • Sebastian Gottschall (BrainSlayer, founder, maindeveloper)
  • Christian Scheele (Chris, CEO)
  • Peter Steinhäuser (CEO)
  • Ankush Malhotra (Maksat)
  • Ales Majdic (Eko, Developer)
  • Sylvain Bothorel (Botho, router webdesign)
  • Felix Fietkau (nbd/openwrt, madwifi)
  • Elke Scheele (Online Shop)
  • Markus Quint (support)
... and a lot of supporters around the world

Supported Hardware click here...
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Thursday, August 13, 2009

Block Traceroute and ping from client

Block Traceroute

You could arrange him in firewall mikrotik, to avoid Traceroute and ping, Along With was the method that most was easy:

/ip firewall filter add chain=forward protocol=icmp icmp-options=11:0 action=drop comment=”Drop Traceroute”
/ip firewall filter add chain=forward protocol=icmp icmp-options=3:3 action=drop comment=”Drop Traceroute”

next you can block ping

/ip firewall filter add chain=input action=accept protocol=icmp limit=50/5s,2

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Avoided Port Scanner from Hacker

To avoid the Port Scanner action from Hacker, then we could arrange in firewall mikrotik, by means of :

1. Make Filter

/ip firewall filter
add chain=input protocol=tcp psd=21,3s,3,1 action=add-src-to-address-list address-list=”port scanners” address-list-timeout=2w comment=”Port scanners to list ” disabled=no

2. Make Chain

add chain=input protocol=tcp tcp-flags=fin,!syn,!rst,!psh,!ack,!urg
action=add-src-to-address-list address-list=”port scanners”
address-list-timeout=2w comment=”NMAP FIN Stealth scan”

add chain=input protocol=tcp tcp-flags=fin,syn
action=add-src-to-address-list address-list=”port scanners”
address-list-timeout=2w comment=”SYN/FIN scan”

add chain=input protocol=tcp tcp-flags=syn,rst
action=add-src-to-address-list address-list=”port scanners”
address-list-timeout=2w comment=”SYN/RST scan”

add chain=input protocol=tcp tcp-flags=fin,psh,urg,!syn,!rst,!ack
action=add-src-to-address-list address-list=”port scanners”
address-list-timeout=2w comment=”FIN/PSH/URG scan”

add chain=input protocol=tcp tcp-flags=fin,syn,rst,psh,ack,urg
action=add-src-to-address-list address-list=”port scanners”
address-list-timeout=2w comment=”ALL/ALL scan”

add chain=input protocol=tcp tcp-flags=!fin,!syn,!rst,!psh,!ack,!urg
action=add-src-to-address-list address-list=”port scanners”
address-list-timeout=2w comment=”NMAP NULL scan”

3. Drop Ip scanning

add chain=input src-address-list=”port scanners” action=drop comment=”dropping port scanners” disabled=no

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Mikrotik Firewall

To pacify router Mikrotik from traffic the virus and excess ping could be used the script firewall mikrotik along with:

1. make script along with used notepad afterwards copy-paste to console mikrotik

/ ip firewall filter
add chain=forward connection-state=established action=accept comment=”allow
established connections” disabled=no
add chain=forward connection-state=related action=accept comment=”allow
related connections” disabled=no
add chain=virus protocol=udp dst-port=135-139 action=drop comment=”Drop
Messenger Worm” disabled=no
add chain=forward connection-state=invalid action=drop comment=”drop invalid
connections” disabled=no
add chain=virus protocol=tcp dst-port=135-139 action=drop comment=”Drop
Blaster Worm” disabled=no
add chain=virus protocol=tcp dst-port=1433-1434 action=drop comment=”Worm”
disabled=no
add chain=virus protocol=tcp dst-port=445 action=drop comment=”Drop Blaster
Worm” disabled=no
add chain=virus protocol=udp dst-port=445 action=drop comment=”Drop Blaster
Worm” disabled=no
add chain=virus protocol=tcp dst-port=593 action=drop comment=”________”
disabled=no
add chain=virus protocol=tcp dst-port=1024-1030 action=drop comment=”________”
disabled=no
add chain=virus protocol=tcp dst-port=1080 action=drop comment=”Drop MyDoom”
disabled=no
add chain=virus protocol=tcp dst-port=1214 action=drop comment=”________”
disabled=no
add chain=virus protocol=tcp dst-port=1363 action=drop comment=”ndm requester”
disabled=no
add chain=virus protocol=tcp dst-port=1364 action=drop comment=”ndm server”
disabled=no
add chain=virus protocol=tcp dst-port=1368 action=drop comment=”screen cast”
disabled=no
add chain=virus protocol=tcp dst-port=1373 action=drop comment=”hromgrafx”
disabled=no
add chain=virus protocol=tcp dst-port=1377 action=drop comment=”cichlid”
disabled=no
add chain=virus protocol=tcp dst-port=2745 action=drop comment=”Bagle Virus”
disabled=no
add chain=virus protocol=tcp dst-port=2283 action=drop comment=”Drop Dumaru.Y”
disabled=no
add chain=virus protocol=tcp dst-port=2535 action=drop comment=”Drop Beagle”
disabled=no
add chain=virus protocol=tcp dst-port=2745 action=drop comment=”Drop
Beagle.C-K” disabled=no
add chain=virus protocol=tcp dst-port=3127 action=drop comment=”Drop MyDoom”
disabled=no
add chain=virus protocol=tcp dst-port=3410 action=drop comment=”Drop Backdoor
OptixPro” disabled=no
add chain=virus protocol=tcp dst-port=4444 action=drop comment=”Worm”
disabled=no
add chain=virus protocol=udp dst-port=4444 action=drop comment=”Worm”
disabled=no
add chain=virus protocol=tcp dst-port=5554 action=drop comment=”Drop Sasser”
disabled=no
add chain=virus protocol=tcp dst-port=8866 action=drop comment=”Drop Beagle.B”
disabled=no
add chain=virus protocol=tcp dst-port=9898 action=drop comment=”Drop
Dabber.A-B” disabled=no
add chain=virus protocol=tcp dst-port=10000 action=drop comment=”Drop
Dumaru.Y, sebaiknya di didisable karena juga sering digunakan utk vpn atau
webmin” disabled=yes
add chain=virus protocol=tcp dst-port=10080 action=drop comment=”Drop
MyDoom.B” disabled=no
add chain=virus protocol=tcp dst-port=12345 action=drop comment=”Drop NetBus”
disabled=no
add chain=virus protocol=tcp dst-port=17300 action=drop comment=”Drop Kuang2″
disabled=no
add chain=virus protocol=tcp dst-port=27374 action=drop comment=”Drop
SubSeven” disabled=no
add chain=virus protocol=tcp dst-port=65506 action=drop comment=”Drop PhatBot,
Agobot, Gaobot” disabled=no
add chain=forward action=jump jump-target=virus comment=”jump to the virus
chain” disabled=no
add chain=input connection-state=established action=accept comment=”Accept
established connections” disabled=no
add chain=input connection-state=related action=accept comment=”Accept related
connections” disabled=no
add chain=input connection-state=invalid action=drop comment=”Drop invalid
connections” disabled=no
add chain=input protocol=udp action=accept comment=”UDP” disabled=no
add chain=input protocol=icmp limit=50/5s,2 action=accept comment=”Allow
limited pings” disabled=no
add chain=input protocol=icmp action=drop comment=”Drop excess pings”
disabled=no
add chain=input protocol=tcp dst-port=1723 action=accept comment=”pptp-server”
disabled=no
add chain=input action=log log-prefix=”DROP INPUT” comment=”Log everything
else” disabled=no
add chain=input action=drop comment=”Drop everything else” disabled=no


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Wednesday, August 12, 2009

Memanfaatkan bekas antena Astro / Indovision untuk WiFi

Disini kita memanfaatkan sebuah Disc ASTRO yang sudah ga dipakai lagi, daripada kebuang sia-sia mendingan kita pakai buat antena WiFi.

Kita siapkan bahan-bahan dulu…..
Bahan yang dibutuhkan adalah:

1. Pipa PVC ukuran 3”, panjang 24cm
2. Tutup pralon / dop pipa ukuran 3” 2buah
3. Tutup pralon / dop pipa ukuran 1” 1buah
4. Mur Baut panjang 2cm
5. Alumunium foil
6. USB WiFi
7. Kabel UTP panjang max 15 Meter
8. Kabel sambungan USB
Bahan yang utama untuk membuat Antena adalah poin 1 – 6, jika sudah mempunyai kabel perpanjangan USB tidak perlu menyiapkan poin 7 & 8.

Langsung aja kita praktek……

a. Ambil dop pipa ukuran 3” & 1”, kita lubang pas ditengah seukuran baut yg sudah kita siapkan. Lalu kita tempelkan secara berlawanan & baut kencang kedua dop pipa tersebut.

DOP tutup pralon

b. Lapisi bagian dalam dop ukuran 3” dengan alumunium foil.

c. Selanjutnya ambil pralon pvc 3”, lubangi seukuran slot USB untuk memasukkan USB
WiFinya, ukuran 5cm dari bibir pralon. Dan buat garis 19cm dari bibir tersebut untuk
area alumunium foil. Dan jangan lupa lapisi bagian luar pralon dengan Alumunium foil.

d. Masukkan USB WiFinya kedalam pralon lalu tutup dengan dop yang telah kita buat tadi. Dop yang ada lapisan alumunium foilnya pasang di sebelah paling dekat dengan lubang USB. Ingat!! Dop paling ujung jangan dilapisi alumunium…..

e. Pasang rangkaian pralon tadi pada tangkai antena ASTRO yang telah kita siapkan.


Selesai sudah prakaria kita, saatnya ujicoba scan sinyal dengan software “Network Stumbler”.

Hasil dari scan sinyal……

Nah selamat berkarya, kalo ada yang bisa bikin lebih sensitif lagi silahkan di share…

source : imfedora.wordpress.com

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Mikrotik v3.20 crack

Tutorial ini saya peroleh dari www.forummikrotik.com dan sudah dicoba dan berhasil

Saya Sudah coba di Hardisk dan berhasil
pake lisensi yang lv6 dan lv4
1. Donwload filenya softwareidcrack-v1.1.rar
2. Install mikrotik seperti biasa, install ROS ver 2.9.51 download di sini
3. ekstrak file softwareidcrack-v1.1.rar hasil downloadnya, didalamnya ada gambar+petunjuknya
4. copy file softwareID crack.v1.1.npk ke mikrotik ROS ver 2.9.51(via Winbox/FTP/WinSCP)
5. reboot mikrotik supaya “softwareID crack” terinstall secara otomatis
6. setelah reboot, buka terminal mikrotik
7. ketik “mikrotik” (tanpa tanda kutip),kalau belum berhasil liat point 15
8. ketik “generate” (tanpa tanda kutip) dan tunggu 10-30 menit
9. biasanya Software ID muncul pertama kali lv.6 dalam 10 menit pertama.
     cocokkan hasil software id dengan daftar yang ada dibawah.
10.kalau berhasil tar ada tulisan Software IDnya berubah
11.jika ada yang lv.6 langsung reboot mikrotiknya, kalo diterusin nanti akan ganti generate lv.5 secara
      otomatis.
12.setelah reboot masuk mikrotik lewat winbox, masukkan key sesuai dengan software id yang di dapat dari
     generate tadi.
     di menu winbox buka System, License, inport key lalu open yang ada dalam daftar dibawah.

13. upgrade ke Mikrotik v3.20

Tutorial upgrade:

       Download package Mikrotik v3.20 disini
       copy file tersebut ke menu FILE mikrotik (via Winbox/FTP/WinSCP)
        setelah di paste di menu FILE kemudian reboot mikrotik.
14. Berhasil (jangan upgrade ver 3.20 keatas, karena key’nya udah di ban ama mikrotik)
15. klo poin 7 ga berhasil ganti commandnya
       mikrotik [enter, lalu] hdb
       mikrotik [enter, lalu] hdc
       mikrotik [enter, lalu] hdd
       mikrotik [enter, lalu] sda
       mikrotik [enter, lalu] sdb
       mikrotik [enter, lalu] sdc
      klo masih gagal coba pindahin Harddisknya dari master ke slave /
      primary ke secondary
16. kalau mau langsung dapet lv.6 pakai command ini:
      mikrotik L6hda
      atau tekan TAB setelah eksekusi command ;mikrotik
      disitu akan tampil aneka command generate.
    
Cara menfilekan key :

buka notepad kemudian copy file
—–BEGIN MIKROTIK SOFTWARE KEY————
rVV1e2RYxT/OM9SZe9OK/0ij55RlWZIYLLmF2DCnMYlo
RbZUCWy+9YIVHRJuVgb9asNXHTAQ/IcHYiQrpBXvvA==
—–END MIKROTIK SOFTWARE KEY————–


kemudian save dengan nama 798Y-K0N.key (extensi key) contoh disini
________________________________________________________
berikut daftar hasil key berdasarkan generate key:
Level 6 Keys
798Y-K0N
—–BEGIN MIKROTIK SOFTWARE KEY————
rVV1e2RYxT/OM9SZe9OK/0ij55RlWZIYLLmF2DCnMYlo
RbZUCWy+9YIVHRJuVgb9asNXHTAQ/IcHYiQrpBXvvA==
—–END MIKROTIK SOFTWARE KEY————–
AK73-PET
—–BEGIN MIKROTIK SOFTWARE KEY————
x+QmBpjxS9quN4UyI2tP2AdybCYZdYWDpKhnkmVWmBZf
31hfbRA2X7ncrHoUI3yAjl6H6ZLwSJKiHXSf6bJAiD==
—–END MIKROTIK SOFTWARE KEY————–
NNFT-86N
—–BEGIN MIKROTIK SOFTWARE KEY————
QcmFFDMuzh87/l2ngPSvD513huBKwgOLXu5tL8yhqPEl
Jns9gKAjxuZ6/Uy9YVFW09riSb1jrvZ7g0uSTVQkhC==
—–END MIKROTIK SOFTWARE KEY————–
Level 5 Keys
FAVD-NFT
—–BEGIN MIKROTIK SOFTWARE KEY————
ZkjCGcuTi8FWBkMTzD9ZAG9QOnjtEPjKTUckhnhEaZ54
oefDJdAvXP26qVQyTHaxFhB40iNMOI18ThwEuVkO1D==
—–END MIKROTIK SOFTWARE KEY————–
LF15-2JT
—–BEGIN MIKROTIK SOFTWARE KEY————
EquSZBusmZSjWg4+6PY7hxPn6HerKbQPDqhO0HY7dZm9
YMwecIIvf1ezBnQS3LBCG0ZLlnO/sloSUqlInguwPC==
—–END MIKROTIK SOFTWARE KEY————–
UNXC-ELT
—–BEGIN MIKROTIK SOFTWARE KEY————
lZDo1eSf3egdI/T2hY8fY8OygIZ+UJucjVfOS2+CY+RT
McnWOukAdhiQj5HlNLr7+jUlVoEqlqvgACA5X2qbLD==
—–END MIKROTIK SOFTWARE KEY————–
VY3P-XNN
—–BEGIN MIKROTIK SOFTWARE KEY————
kIv65f9YRZE4Q22rtFScDxPT6pji+AT+BYlatE3WAqui
k1jbsrE7vxcoXQc3WjSzz6gQ9NHIPRzRxg2X6dtQ4A==
—–END MIKROTIK SOFTWARE KEY————–
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Saturday, August 8, 2009

Tips Meningkatkan Keamanan Jaringan Anda

Seperti yang kita lihat di saat ini, Internet telah tumbuh dan berkembang hingga mencapai angka beberapa juta unit komputer yang terkoneksi di berbagai belahan dunia. Dari hari ke hari pula informasi yang terkandung di dalam jaringan Internet tersebut semakin lengkap, akurat, dan penting. . Informasi telah menjadi suatu asset yang sedemikian berharga sehingga perlu mendapat perlakuan yang lebih spesifik. Selain itu pula, kemajuan yang dicapai dalam bidang pengembangan sistem operasi komputer sendiri dan utulitasnya sudah sedemikian jauh dimana tingkat performansi, keandalan dan fleksibilitas software menjadi kriteria utama dalam proses pengembangan software. Dengan semakin penting dan berharganya informasi tersebut dan ditunjang oleh kemajuan pengembangan software, tentunya menarik minat para pembobol (hacker) dan penyusup (intruder) untuk terus bereksperimen guna menemukan dan mempergunakan setiap kelemahan yang ada dari konfigurasi sistem informasi yang telah ditetapkan

Bertolak dari kenyataan di atas, muncul sebuah konsep yang lebih sering disebut dengan Network Security. Pada awalnya, konsep ini menjelaskan lebih banyak mengenai keterjaminan (security) dari sebuah sistem jaringan komputer yang terhubung ke Internet terhadap ancaman dan gangguan yang ditujukan kepada sistem tersebut. Cakupan konsep tersebut semakin hari semakin luas sehingga pada saat ini tidak hanya membicarakan masalah keterjaminan jaringan komputer saja, tetapi lebih mengarah kepada masalah-masalah keterjaminan sistem jaringan informasi secara global. Beberapa negara Eropa dan Amerika bahkan telah menjadikan Network Security menjadi salah satu titik sentral perhatian pihak-pihak militer masing-masing.

Sebenarnya, masalah Network Security ini timbul dari konektivitas jaringan komputer lokal yang kita miliki dengan wide-area network (seperti Internet). Jadi, selama jaringan lokal komputer kita tidak terhubung kepada wide-area network, masalah Network Security tidak begitu penting. Tetapi hal ini bukan berarti memberikan arti bahwa bergabung dengan wide-area network adalah suatu hal yang ‘menakutkan’ dan penuh bahaya. Network Security hanyalah menjelaskan kemungkinan-kemungkinan yang akan timbul dari konektivitas jaringan komputer lokal kita dengan wide-area network.

Secara umum, terdapat 3 (tiga) kata kunci dalam konsep Network Security ini, yaitu:

  • resiko / tingkat bahaya,
  • ancaman, dan
  • kerapuhan sistem (vulnerability)

Resiko atau tingkat bahaya
Dalam hal ini, resiko berarti berapa besar kemungkinan keberhasilan para penyusup dalam rangka memperoleh akses ke dalam jaringan komputer lokal yang dimiliki melalui konektivitas jaringan lokal ke wide-area network. Secara umum, akses-akses yang diinginkan adalah :

  • Read Access : Mampu mengetahui keseluruhan sistem jaringan informasi.
  • Write Access : Mampu melakukan proses menulis ataupun menghancurkan data yang terdapat di sistem tersebut.
  • Denial of Service : Menutup penggunaan utilitas-utilitas jaringan normal dengan cara menghabiskan jatah CPU, bandwidth maupun memory.

Ancaman
Dalam hal ini, ancaman berarti orang yang berusaha memperoleh akses-akses illegal terhadap jaringan komputer yang dimiliki seolah-olah ia memiliki otoritas terhadap akses ke jaringan komputer.

Kerapuhan System (Vulnerability)
Kerapuhan sistem lebih memiliki arti seberapa jauh proteksi yang bisa diterapkan kepada network yang dimiliki dari seseorang dari luar sistem yang berusaha memperoleh akses illegal terhadap jaringan komputer tersebut dan kemungkinan orang-orang dari dalam sistem memberikan akses kepada dunia luar yang bersifat merusak sistem jaringan.

Untuk menganalisa sebuah sistem jaringan informasi global secara keseluruhan tentang tingkat keandalan dan keamanannya bukanlah suatu hal yang mudah dilaksanakan. Analisa terhadap sebuah sistem jaringan informasi tersebut haruslah mendetil mulai dari tingkat kebijaksanaan hingga tingkat aplikasi praktisnya.

Sebagai permulaan, ada baiknya kita melihat sebuah sistem jaringan yang telah menjadi titik sasaran utama dari usaha-usaha percobaan pembobolan tersebut. Pada umumnya, jaringan komputer di dunia menggunakan sistem operasi Unix sebagai platform. Unix telah menjadi sebuah sistem operasi yang memiliki keandalan tinggi dan tingkat performansi yang baik. Tetapi, pada dasarnya Unix tersusun oleh fungsi-fungsi yang cukup rumit dan kompleks. Akibatnya, Unix juga memiliki beberapa kelemahan seperti bug-bug (ketidaksesuaian algoritma pemrograman) kecil yang kadang kala tidak disadari oleh para pemrogram Unix. Selain itu, utilitas-utilitas yang memanfaatkan Unix sebagai platformnya, seringkali mempunyai bug-bug tersendiri pula. Nah, hal-hal inilah yang sering dieksploitasi oleh para hacker dan intruder di seluruh dunia.

Guna mencegah berhasilnya eksploitasi para hacker dan intruder tersebut, dikembangkan sebuah konsep yang dikenal dengan UNIX Network Security Architecture. Arsitektur ini mencakup 7 lapis tingkat sekuriti pada jaringan. Ketujuh lapis tersebut adalah sebagai berikut :

  • Lapis ke-7 : Kebijaksanaan
  • Lapis ke-6 : Personil
  • Lapis ke-5 : Local Area Network
  • Lapis ke-4 : Batas Dalam Jaringan
  • Lapis ke-3 : Gateway
  • Lapis ke-2 : Paket Filtering
  • Lapis ke-1 : Batas Luar Jaringan

Kebijaksanaan
Lapis kebijaksanaan menjadi pelindung terhadap keseluruhan program proteksi dan sekuriti jaringan yang diterapkan. Lapis ini mempunyai fungsi mendefinisikan kebijakan-kebijakan organisasi mulai dari resiko yang paling besar yang mungkin didapat hingga bagaimana mengimplementasikan kebijaksanaan yang diambil terhadap prosedur-prosedur dasar dan peralatan yang digunakan. Lapis ini menjadi salah satu penentu utama keberhasilan program proteksi dan sekuriti sistem.

Personil
Lapis ini mendefinisikan segi manusia dalam sistem jaringan informasi. Personil yang melakukan instalasi, konfigurasi, pengoperasian hingga orang-orang yang mampu menjalankan akses-akses yang tersedia di sistem adalah termasuk dalam lapis ini. Kebijakan yang diambil pada lapis ini pada dasarnya harus mencerminkan tujuan-tujuan yang ingin dicapai dalam program proteksi dan sekuriti ini.

Local Area Network
Lapis selanjutnya mendefinisikan peralatan-peralatan dan data-data yang harus mendapatkan proteksi. Selain itu, lapis ini juga mencakup prosedur-prosedur pengawasan dan kontrol yang sering diterapkan dalam sistem.

Batas Dalam Jaringan Batas
Dalam Jaringan mendefinisikan lapisan sistem yang terkoneksi secara fisik ke daerah “penyangga” yang menjadi pemisah antara sistem jaringan informasi lokal dengan jaringan luar. Batas ini menjadi penting karena titik ini menjadi sasaran utama usaha-usaha eksploitasi untuk memperoleh akses illegal. Ada baiknya daerah penyangga ini dikonsentrasikan pada satu titik sehingga penerapan prosedur pengawasan dan kontrol menjadi lebih mudah. Demikian pula bila datang serangan dari luar sistem, hanya akan terdapat satu titik masuk yang paling utama. Dengan demikian, akan lebih mudah mengisolasi sistem yang dimiliki dari konektivitas ke luar bila terjadi gangguan.

Gateway
Gateway mendefinisikan menjadi pintu utama dari dan ke sistem yang dimiliki. Kebijaksanaan proteksi dan sekuriti sebuah sistem yang terkoneksi dengan wide-area network seharusnya lebih mengarahkan usaha-usaha yang ada untuk mengamankan lapis ini sebaik mungkin. Servis-servis publik ada baiknya diletakkan pada lapis tersebut guna meminimisasi kemungkinan akses yang lebih jauh ke dalam sistem.

Paket Filtering
Lapis ini mendefinisikan platform yang berada di antara network interface lapis 3 (gateway) dengan network interface yang menjadi tempat penerapan metoda Firewall. Lapis tersebut lebih bersifat sebagai program yang menjalankan fungsi pengawasan (monitoring) terhadap paket-paket data yang masuk maupun yang keluar sistem.

Batas Luar Jaringan
Batas Luar Jaringan mendefinisikan titik dimana sistem terhubung dengan wide-area network dan kita tidak memiliki kontrol langsung terhadap titik tersebut.

Seperti yang telah dijabarkan di atas, lapis ke-3 menjadi titik utama dan yang paling rawan dalam network security ini. Implementasi kebijaksanaan yang diambil pada layer ini hanya bisa dilakukan secara software. Terdapat beberapa jenis security software yang bisa digunakan untuk memperkuat usaha proteksi dan sekuriti sistem pada lapis ke-3 ini. Di antaranya adalah :

TCP Wrapper
Program ini menyediakan layanan monitoring dan kontrol terhadap network services. Pada dasarnya, yang dilakukan oleh program ini adalah membuat daftar log mengenai aktivitas-aktivitas hubungan yang terjadi. Program ini dapat diambil secara gratis melalui anonymous FTP via ftp.cert.org yang terletak pada direktori pub/tools/tcp_wrappers/tcp_wrappers.*

Swatch
Program Swatch menggabungkan daftar-daftar log yang telah diciptakan oleh program-program utilitas lain di samping kelebihannya yang mampu dikonfigurasi sehingga pada saat melakukan logging, Swatch bisa melakukan aksi lain berdasar pada prioritas-prioritas tertentu. Swatch tersedia melalui anonymous FTP dari sierra.stanford.edu pada direktori pub/sources.

SOCKS library dan sockd
Program ini menjadi alternatif lain dari implementasi konsep “TCP Wrapper”. Kegunaan utama program ini adalah mengkonsentrasikan semua layanan umum internet pada suatu titik. “sockd” dijalankan oleh “inetd” pada saat permintaan layanan tertentu muncul dan hanya memperbolehkan koneksi dari host-host yang telah terdaftar. Program ini tentu saja juga melakukan aktivitas log yang berkaitan dengan koneksi yang terjadi. Program ini dapat diperoleh melalui anonymous FTP pada host s1.gov pada direktori /pub dengan nama socks.tar.Z.

Source : Joko Yuliantoro & Onno W. Purbo

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Type dan Jenis Kabel

Rasanya kurang lengkap, seperti “sayur tanpa garam”, kalo berbicara soal jaringan ngak menyentuh mengenai perkabelan, karena kita ketahui bahwa kabel merupakan salah satu bagian yang terpenting dalam hal koneksi jaringan, berikut ini akan secara ringkas dijelaskan mengenai tipe dan jenis kabel yang biasa digunakan dalam sebuah jaringan .. meski sedikit dan ngak panjang lebar tapi mudah-mudahan dapat bermanfaat.

Setiap jenis kabel mempunyai kemampuan dan spesifikasinya yang berbeda, pengenalan tipe kabel. Ada dua jenis kabel yang dikenal secara umum,

  1. UTP unshielded twisted pair,
  2. STP shielded twisted pair
  3. Coaxial cable.

Kategori untuk twisted pair yaitu (hingga saat ini), yaitu:

kabel11.jpg

Pemberian kategori 1/2/3/4/5/6 merupakan kategori spesifikasi untuk masing-masing kabel tembaga dan juga untuk jack. Masing-masing merupakan seri revisi atas kualitas kabel, kualitas pembungkusan kabel (isolator) dan juga untuk kualitas “belitan” (twist) masing-masing pasang kabel. Selain itu juga untuk menentukan besaran frekuensi yang bisa lewat pada sarana kabel tersebut, dan juga kualitas isolator sehingga bisa mengurangi efek induksi antar kabel (noise bisa ditekan sedemikian rupa).

Perlu diperhatikan juga, spesifikasi antara CAT5 dan CAT5 enchanced mempunyai standar industri yang sama, namun pada CAT5e sudah dilengkapi dengan insulator untuk mengurangi efek induksi atau electromagnetic interference. Kabel CAT5e bisa digunakan untuk menghubungkan network hingga kecepatan 1Gbps.

Sedangkan untuk coaxial cable, dikenal dua jenis, yaitu thick coaxial cable (mempunyai diameter lumayan besar) dan thin coaxial cable (mempunyai diameter lebih kecil).

Thick coaxial cable (Kabel Coaxial “gemuk”)

Kabel coaxial jenis ini dispesifikasikan berdasarkan standar IEEE 802.3 10BASE5, dimana kabel ini mempunyai diameter rata-rata 12mm, dan biasanya diberi warna kuning; kabel jenis ini biasa disebut sebagai standard ethernet atau thick Ethernet, atau hanya disingkat ThickNet, atau bahkan cuman disebut sebagai yellow cable.

Kabel Coaxial ini (RG-6) jika digunakan dalam jaringan mempunyai spesifikasi dan aturan sebagai berikut:

  • Setiap ujung harus diterminasi dengan terminator 50-ohm (dianjurkan menggunakan terminator yang sudah dirakit, bukan menggunakan satu buah resistor 50-ohm 1 watt, sebab resistor mempunyai disipasi tegangan yang lumayan lebar).
  • Maksimum 3 segment dengan peralatan terhubung (attached devices) atau berupa populated segments.
  • Setiap kartu jaringan mempunyai pemancar tambahan (external transceiver).
  • Setiap segment maksimum berisi 100 perangkat jaringan, termasuk dalam hal ini repeaters.
  • Maksimum panjang kabel per segment adalah 1.640 feet (atau sekitar 500 meter).
  • Maksimum jarak antar segment adalah 4.920 feet (atau sekitar 1500 meter).
  • Setiap segment harus diberi ground.
  • Jarang maksimum antara tap atau pencabang dari kabel utama ke perangkat (device) adalah 16 feet (sekitar 5 meter).
  • Jarang minimum antar tap adalah 8 feet (sekitar 2,5 meter).

Thin coaxial cable (Kabel Coaxial “Kurus”)

Kabel coaxial jenis ini banyak dipergunakan di kalangan radio amatir, terutama untuk transceiver yang tidak memerlukan output daya yang besar. Untuk digunakan sebagai perangkat jaringan, kabel coaxial jenis ini harus memenuhi standar IEEE 802.3 10BASE2, dimana diameter rata-rata berkisar 5mm dan biasanya berwarna hitam atau warna gelap lainnya. Setiap perangkat (device) dihubungkan dengan BNC T-connector. Kabel jenis ini juga dikenal sebagai thin Ethernet atau ThinNet.

Kabel coaxial jenis ini, misalnya jenis RG-58 A/U atau C/U, jika diimplementasikan dengan

Tconnector dan terminator dalam sebuah jaringan, harus mengikuti aturan sebagai berikut:

  • Setiap ujung kabel diberi terminator 50-ohm.
  • Panjang maksimal kabel adalah 1,000 feet (185 meter) per segment.
  • Setiap segment maksimum terkoneksi sebanyak 30 perangkat jaringan (devices)
  • Kartu jaringan cukup menggunakan transceiver yang onboard, tidak perlu tambahan transceiver, kecuali untuk repeater.
  • Maksimum ada 3 segment terhubung satu sama lain (populated segment).
  • Setiap segment sebaiknya dilengkapi dengan satu ground.
  • Panjang minimum antar T-Connector adalah 1,5 feet (0.5 meter).
  • Maksimum panjang kabel dalam satu segment adalah 1,818 feet (555 meter).
  • Setiap segment maksimum mempunyai 30 perangkat terkoneksi.

kabel21.jpg

UTP Cable (khususnya CAT5 / CAT5e)

kabel3.jpg

Connector yang bisa digunakan untuk UTP Cable CAT5 adalah RJ-45. Untuk penggunaan koneksi komputer, dikenal 2 buah tipe penyambungan kabel UTP ini, yaitu straight cable dan crossover cable. Fungsi masing-masing jenis koneksi ini berbeda, straight cable digunakan untuk menghubungkan client ke hub/router, sedangkan crossover cable digunakan untuk menghubungkan client ke client atau dalam kasus tertentu digunakan untuk menghubungkan hub ke hub.

Straight Cable

Menghubungkan ujung satu dengan ujung lain dengan satu warna, dalam artian ujung nomor satu merupakan ujung nomor dua di ujung lain. Sebenarnya urutan warna dari masing-masing kabel tidak menjadi masalah, namun ada standard secara internasional yang digunakan untuk straight cable ini, yaitu :

Koneksi minimum berdasarkan standar EIA/TIA-568B RJ-45 Wiring Scheme :

Pair#2 is connected to pins 1 and 2 like this:

Pin 1 wire color: white/orange

Pin 2 wire color: orange

Pair#3 is connected to pins 3 and 6 like this:

Pin 3 wire color: white/green

Pin 6 wire color: green

Sedangkan sisa kabel-nya dihubungkan sebagai berikut

Pair#1

Pin 4 wire color: blue

Pin 5 wire color: white/blue

Pair#4

Pin 7 wire color: white/brown

Pin 8 wire color: brown

kabel4.jpg

Crossover Cable

kabel51.jpg

Dasar Koneksi Untuk UTP Crossover Cable

kabel6.jpg

pin 1 -> pin 3, pin 2 -> pin 6, pin 3 -> pin 1, and pin 6 -> pin 2. Pin lainnya dibiarkan tidak terhubung

kabel7.jpg

Source : dedenthea.wordpress.com

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Pengantar TCP/IP

TCP/IP ?
Transmission Control Protocol/Internet Protocol (TCP/IP) adalah protokol yang dikembangkan sebagai bagian dari penelitian yang dilakukan oleh “Defense Advanced Research Projects Agency” (DARPA).

TCP/IP Internet

TCP/IP adalah salah satu jenis protokol (aturan) yg memungkinkan kumpulan komputer dapat berkomunikasi dan bertukar data di dalam suatu network (jaringan). Selain Internet, TCP/IP juga dapat diterapkan pada jaringan LAN dan WAN.

Model Jaringan TCP/IP
Susunan Model jaringan TCP/IP sangat mirip dengan referensi model dari OSI pada “lower layer”, yaitu pada layer 1 “physical” dan layer 2 “data-link”. Berikut ilustrasi perbandingan model OSI dan TCP/IP

OSI vs TCP/IP Model

Catatan : Layer “physical” dan “data link” dari susunan TCP/IP sering disebut “network interface layer”.

Datagram TCP/IP
Informasi TCP/IP ditransfer dalam sebuah urutan “datagram”. Satu pesan ditransfer sebagai rentetan datagram yang disusun kembali menjadi seperti pesan semula pada sisi penerima.

Layer Protocol TCP/IP
Ilustrasi berikut menggambarkan susunan tiga layer dari Protokol TCP/IP:

  • Application Layer
  • Transport Layer
  • Internet Layer

TCP IP upper Layer
.
Mengenal TCP

TCP adalah connection oriented, protocol handal yang berada pada Layer Transport dari TCP/IP Protocol Stack.

Fungsi TCP
Berikut ini adalah fungsi umum TCP Protocol:

  • TCP bertugas memecah pesan-pesan menjadi beberapa segment, menyatukan kembali (reassemble) pada stasiun tujuan, mengirimkan kembali apapun yang tidak diterima, dan menyatukan kembali pesan-pesan tersebut dari beberapa segment.
  • TCP menyediakan sirkuit virtual antara aplikasi end-user.
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