Tabel Subnet Mask

Ini adalah tabel subnet mask yang bermanfaat bagi  para pembangun jaringan untuk menentukan berapa jumlah host atau jumlah subnet dari kelas jaringan tertentu yang akan disediakan nantinya.

Class B                   Effective  Effective
# bits        Mask         Subnets     Hosts
-------  ---------------  ---------  ---------
  2      255.255.192.0           2     16382
  3      255.255.224.0           6      8190
  4      255.255.240.0          14      4094
  5      255.255.248.0          30      2046
  6      255.255.252.0          62      1022
  7      255.255.254.0         126       510
  8      255.255.255.0         254       254
  9      255.255.255.128       510       126
  10     255.255.255.192      1022        62
  11     255.255.255.224      2046        30
  12     255.255.255.240      4094        14
  13     255.255.255.248      8190         6
  14     255.255.255.252     16382         2

Class C                   Effective  Effective
# bits        Mask         Subnets     Hosts
——-  —————  ———  ———
  2      255.255.255.192      2         62
  3      255.255.255.224      6         30
  4      255.255.255.240     14         14
  5      255.255.255.248     30          6
  6      255.255.255.252     62          2

Class A                   Effective  Effective
# bits        Mask         Subnets     Hosts
——-  —————  ———  ———
  2      255.192.0.0            2      4194302
  3      255.224.0.0            6      2097150
  4      255.240.0.0           14      1048574
  5      255.248.0.0           30       524286
  6      255.252.0.0           62       262142
  7      255.254.0.0          126       131070
  8      255.255.0.0          254        65534
  9      255.255.128.0        510        32766
  10     255.255.192.0       1022        16382
  11     255.255.224.0       2046         8190
  12     255.255.240.0       4094         4094
  13     255.255.248.0       8190         2046
  14     255.255.252.0      16382         1022
  15     255.255.254.0      32766          510
  16     255.255.255.0      65534          254
  17     255.255.255.128   131070          126
  18     255.255.255.192   262142           62
  19     255.255.255.224   524286           30
  20     255.255.255.240  1048574           14
  21     255.255.255.248  2097150            6
  22     255.255.255.252  4194302            2

ket. : tidak termasuk subnet dan host yang bernilai 1 atau 0 semua Read more...

Kabel Cross RJ-45

Membuat kabel cross RJ-45 mudah kok, hafalinnya juga mudah. Biasanya kabel cross digunakan untuk menghubungkan dua komputer tanpa menggunakan hub/switch. Selain itu kabel cross juga digunakan untuk menghubungkan dua CSU/DSU untuk keperluan tes konfigurasi WAN. 

Kita tinggal mengingat kabel mana aja yang akan di-cross dengan melihat urutan kabelnya. Kabel UTP RJ-45 terdiri dari 8 kabel kan? nah yang akan di-cross tuh cuma kabel yang ke-1, 2, 3 dan 6 pada kedua ujung kabel. Bagaimana nge-crossnya, nah yang perlu diingat kabel pertama pada satu sisi disilang ke kabel ketiga di ujung lain, kabel kedua pada satu sisi disilang ke kabel keenam pada ujung lain, dan begitu pula sebaliknya. Jadi 1 ke 3, 2 ke 6 dan 3 ke 1, 6 ke 2. Kalo masih bingung lihat skema di bawah.

konektor   konektor
  RJ45          RJ45
----------------------
  pin 1   ->   pin 3
  pin 2   ->   pin 6
  pin 3   ->   pin 1
  pin 6   ->   pin 2

Read more...

Routix NetCom

Routix NetCom introduces easy-to-use rules-based packets-level filtering and managment software and improved remote management features and remote scripting. NetCom is an extensible firewall, traffic controller and traffic statistics software for the Microsoft Windows™ NT, XP, 2000 and 2003 operating system. NetCom provides firewall that helps protect network resources from viruses and hackers. NetCom provides a unified management console that simplifies security and access management.

Each rule can be configured with many conditions: connections count, packets direction, NICs, protocols, MAC-addresses, IP-addresses, TCP and UDP ports, time and other conditions.
Each rule can be configured with many actions: packets can be allowed, dropped or sended to the next rule in list. URL filtering supported. Rule can replace MAC and IP addresses, TCP and UDP ports (for example packets can be redirected to the transparent proxy, like SquidNT). Rule can make backward replacements automatically (via NAT-table). Rule can bridge packets between two or more NICs. Rule can redirect packets from one to other NIC. Rule can limit incoming and outgoing bandwidth or prioriterize defined traffic. Rule can execute scripts or external executables on misc events. Each rule has counters of incoming and outgoing traffic. These counters can be resetted automatically with any specified interval. Also these counters can be used as conditions (for example you can block any or specified traffic if counter > N).

Download from Routix.net

Read more...

What is Wi-Fi - Overview

"Wi-Fi" is a play on the old audio term "Hi-Fi" (high fidelity). The term also has been trademarked by the Wi-Fi Alliance (formerly the Wireless Ethernet Compatibility Alliance). Today, Wi-Fi is most commonly used to describe a wireless local area network based on the IEEE 802.11 series of standards, which is a set of wireless technical specifications issued by the Institute of Electrical and Electronic Engineers (IEEE). The IEEE is an international professional organization for electrical and electronics engineers, with formal links with the International Organization for Standardization (more commonly known as the "ISO").

The IEEE 802.11 standards specify an "over-the-air" interface consisting of radio frequency (RF) technology to transmit and receive data between a wireless client and a base station or access point (an "infrastructure" configuration), as well as among two or more wireless clients that happen to be within communications range of each other (an "ad hoc" configuration).

The IEEE 802.11 standards resolve compatibility issues between manufacturers of wireless networking equipment operating in specific frequency bands within the unlicensed spectra of 2.4 GHz and 5 GHz. (Unlicensed spectrum refers to airwaves that haven't been allocated to an exclusive user.) This wireless, flexible data communications system can be implemented either as an extension to, or as an alternative for, a wired local area network (LAN). As such, it is a wireless networking standard that's accepted worldwide and, consequently, has rapidly gained acceptance as an alternative to conventional wireline technologies.

The term "Wi-Fi" began life a few years ago as the IEEE 802.11 High Rate (HR) Standard, which later became known as the IEEE 802.11b standard. Originally, "Wi-Fi" was used only in place of the 802.11b standard (operating at 2.4 GHz and 11 Mbps), in the same way that the term "Ethernet" is used in place of the wired LAN standard, IEEE 802.3. However, in October 2002, the Wi-Fi Alliance extended the "Wi-Fi" trademark to include both 802.11b and its higher-bandwidth brother, 802.11a (54 Mbps).

In case you're wondering, 802.11g will also fall under the Wi-Fi banner. Furthermore, since in many ways, 802.11g is a higher-bandwidth version of the 802.11b specification, the Wi-Fi Alliance also has stated that when it does certify 802.11g products as interoperable, the organization won't label them "802.11g." Instead, it plans on calling such products "54 Mbps 802.11b," because focus groups of potential customers have shown that users are confused by the alphabet soup nature of the IEEE's designations for the various 802.11 standards.

Note : Specific groups, known as "Task Groups" inside the 802.11 standards body oversee enhancements ranging from bandwidth to specific portions of the 802.11 standard. The appearance of each new "flavor" of the technology results in a new suffix to 802.11, i.e. 802.11a, 802.11b, up to 802.11n. While there is a method for the IEEE standards naming scheme, the alphanumeric nature of these standards can be confusing, which is why the moniker "Wi-Fi" caught on. A complete technical discussion of each individual specification or standard can be found in Chapter 6.
Ultimately, the term "Wi-Fi" will probably end up as a generic description of all 802.11 networks, in much the same way that "Ethernet" is used to describe all IEEE 802.3 networks. Coincidentally, since 802.11 networks are considered wireless extensions of wired Ethernet, they can handle conventional networking protocols such as TCP/IP, AppleTalk and PC file sharing standards.

The opportunity for wireless data communication in the United States and elsewhere is huge. According to the research firm Gartner, Inc., as revealed in its Dataquest Market Analysis Perspective entitled, "Wireless Data in the United States: Pieces of the Puzzle are Missing, but a Picture is Taking Shape," more than 25 million of the U.S.'s 112.1 million workforce have a mobile job requirement and that number is steadily increasing.

From: Going Wi-Fi A Practical to Planning and Building an 802.11 Network by Janice Reynolds

Read more...