Wireless Media

The IEEE and telecommunications industry standards for wireless data communications cover both the Data Link and Physical layers. Four common data communications standards that apply to wireless media are:
Standard IEEE 802.11 - Commonly referred to as Wi-Fi, is a Wireless LAN (WLAN) technology that uses a contention or non-deterministic system with a Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) media access process.
Standard IEEE 802.15 - Wireless Personal Area Network (WPAN) standard, commonly known as "Bluetooth", uses a device pairing process to communicate over distances from 1 to 100 meters.
Standard IEEE 802.16 - Commonly known as Worldwide Interoperability for Microwave Access (WiMAX), uses a point-to-multipoint topology to provide wireless broadband access.
Global System for Mobile Communications

Standard IEEE 802.16 - Commonly known as Worldwide Interoperability for Microwave Access (WiMAX), uses a point-to-multipoint topology to provide wireless broadband access.
Global System for Mobile Communications (GSM) - Includes Physical layer specifications that enable the implementation of the Layer 2 General Packet Radio Service (GPRS) protocol to provide data transfer over mobile cellular telephony networks.

Other wireless technologies such as satellite communications provide data network connectivity for locations without another means of connection. Protocols including GPRS enable data to be transferred between earth stations and satellite links.

Wireless Media

Wireless media carry electromagnetic signals at radio and microwave frequencies that represent the binary digits of data communications. As a networking medium, wireless is not restricted to conductors or pathways, as are copper and fiber media.

Wireless data communication technologies work well in open environments. However, certain construction materials used in buildings and structures, and the local terrain, will limit the effective coverage. In addition, wireless is susceptible to interference and can be disrupted by such common devices as household cordless phones, some types of fluorescent lights, microwave ovens, and other wireless communications.

Further, because wireless communication coverage requires no access to a physical strand of media, devices and users who are not authorized for access to the network can gain access to the transmission. Therefore, network security is a major component of wireless network administration.

Single and Multimode

Single-mode optical fiber carries a single ray of light, usually emitted from a laser. Because the laser light is uni-directional and travels down the center of the fiber, this type of fiber can transmit optical pulses for very long distances.

Multimode fiber typically uses LED emitters that do not create a single coherent light wave. Instead, light from an LED enters the multimode fiber at different angles. Because light entering the fiber at different angles takes different amounts of time to travel down the fiber, long fiber runs may result in the pulses becoming blurred on reception at the receiving end. This effect, known as modal dispersion, limits the length of multimode fiber segments.

Multimode fiber, and the LED light source used with it, are cheaper than single-mode fiber and its laser-based emitter technology.

Copper Media

The most commonly used media for data communications is cabling that uses copper wires to signal data and control bits between network devices. Cabling used for data communications usually consists of a series of individual copper wires that form circuits dedicated to specific signaling purposes.

Other types of copper cabling, known as coaxial cable, have a single conductor that runs through the center of the cable that is encased by, but insulated from, the other shield. The copper media type chosen is specified by the Physical layer standard required to link the Data Link layers of two or more network devices.

These cables can be used to connect nodes on a LAN to intermediate devices, such as routers and switches. Cables are also used to connect WAN devices to a data services provider such as a telephone company. Each type of connection and the accompanying devices have cabling requirements stipulated by Physical layer standards.

Signal Patterns

One way to provide frame detection is to begin each frame with a pattern of signals representing bits that the Physical layer recognizes as denoting the start of a frame. Another pattern of bits will signal the end of the frame. Signal bits not framed in this manner are ignored by the Physical layer standard being used.

Valid data bits need to be grouped into a frame; otherwise, data bits will be received without any context to give them meaning to the upper layers of the networking model. This framing method can be provided by the Data Link layer, the Physical layer, or by both.

The figure depicts some of the purposes of signaling patterns. Signal patterns can indicate: start of frame, end of frame, and frame contents. These signal patterns can be decoded into bits. The bits are interpreted as codes. The codes indicate where the frames start and stop.

The three fundamental functions of the Physical layer are

The three fundamental functions of the Physical layer are:
The physical components
Data encoding
Signaling

The physical elements are the electronic hardware devices, media and connectors that transmit and carry the signals to represent the bits.

Encoding

Encoding is a method of converting a stream of data bits into a predefined code. Codes are groupings of bits used to provide a predictable pattern that can be recognized by both the sender and the received. Using predictable patterns helps to distinguish data bits from control bits and provide better media error detection.

In addition to creating codes for data, encoding methods at the Physical layer may also provide codes for control.

purposes such as identifying the beginning and end of a frame. The transmitting host will transmit the specific pattern of bits or a code to identify the beginning and end of the frame.

Signaling

The Physical layer must generate the electrical, optical, or wireless signals that represent the "1" and "0" on the media. The method of representing the bits is called the signaling method. The Physical layer standards must define what type of signal represents a "1" and a "0". This can be as simple as a change in the level of an electrical signal or optical pulse or a more complex signaling method.

Cisco RV120W Wireless-N VPN Firewall - Router

Cisco RV120W Wireless-N VPN Firewall - Router
The Cisco RV120W Wireless-N VPN Firewall combines highly secure connectivity - to the Internet as well as from other locations and remote workers - with a high-speed, 802.11n wireless access point, a 4-port switch, an intuitive, browser-based device manager, and support for the Cisco FindIT Network Discovery Utility, all at a very affordable price. The Cisco RV120W Wireless-N VPN Firewall's combination of high performance, business-class features and top-quality user experience takes basic connectivity to a new level.

What It Is and Why You Need It

High-speed, standards-based 802.11n wireless connectivity to help employees stay productive while away from their desks
Integrated 4-port 10/100 switch with quality of service (QoS) support for enhanced voice, video and data traffic
Support for separate 'virtual' networks enables you to control access to sensitive information and to set up highly secure wireless guest access
IP Security (IPsec) VPN support with hardware acceleration to deliver highly secure, high-performance connections to multiple locations and traveling employees.

Call or email today for a quote.

Refurbished Cisco ASA Call today for a quote.

[REFURBISHED] Cisco ASA 5505 10-User Bundle Firewall - 6 x 10/100Base-TX LAN, 2 x 10/100Base-TX PoE LAN - 1 x SSC
 

Cisco Aironet

Cisco Aironet 1130AG Series IEEE 802.11a/b/g access points provide high-capacity, high-security, enterprise-class features in an unobtrusive, office-class design, delivering WLAN access with the lowest total cost of ownership. With high-performing dual IEEE 802.11a and 802.11g radios, the Cisco Aironet 1130AG Series provides a combined capacity of up to 108 Mbps to meet the needs of growing WLANs. Hardware-assisted Advanced Encryption Standard (AES) or temporal key integrity protocol (TKIP) encryption provides uncompromised support for interoperable IEEE 802.11i, Wi-Fi Protected Access 2 (WPA2) or WPA security. Orderable supporting either Cisco IOS Software, or the Lightweight Access Point Protocol (LWAPP), the Cisco Aironet 1130AG Series uses radio and network management features for simplified deployment, along with built-in omnidirectional antennas that provide robust and predictable WLAN coverage for offices and similar RF environments. In addition, when running Cisco IOS Software the Cisco Aironet 1130AG Series supports both access point and workgroup bridge functionality. The competitively priced Cisco Aironet 1130AG Series is ready to install and easy to manage, reducing the cost of deployment and ongoing maintenance.

CCNA class notes.

Long before desktop computers with sophisticated graphical interfaces existed, people used text-based systems which were often just display terminals physically attached to a central computer. Once networks were available, people needed a way to remotely access the computer systems in the same manner that they did with the directly attached terminals.
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Telnet was developed to meet that need. Telnet dates back to the early 1970s and is among the oldest of the Application layer protocols and services in the TCP/IP suite. Telnet provides a standard method of emulating text-based terminal devices over the data network. Both the protocol itself and the client software that implements the protocol are commonly referred to as Telnet.
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Appropriately enough, a connection using Telnet is called a Virtual Terminal (VTY) session, or connection. Rather than using a physical device to connect to the server, Telnet uses software to create a virtual device that provides the same features of a terminal session with access to the server command line interface (CLI).
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To support Telnet client connections, the server runs a service called the Telnet daemon. A virtual terminal connection is established from an end device using a Telnet client application. Most operating systems include an Application layer Telnet client. On a Microsoft Windows PC, Telnet can be run from the command prompt. Other common terminal applications that run as Telnet clients are HyperTerminal, Minicom, and TeraTerm.
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Once a Telnet connection is established, users can perform any authorized function on the server, just as if they were using a command line session on the server itself. If authorized, they can start and stop processes, configure the device, and even shut down the system
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Telnet is a client/server protocol and it specifies how a VTY session is established and terminated. It also provides the syntax and order of the commands used to initiate the Telnet session, as well as control commands that can be issued during a session. Each Telnet command consists of at least two bytes. The first byte is a special character called the Interpret as Command (IAC) character. As its name implies, the IAC defines the next byte as a command rather than text.
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Some sample Telnet protocol commands include:
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Are You There (AYT) - Lets the user request that something appear on the terminal screen to indicate that the VTY session is active.
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Erase Line (EL) - Deletes all text from the current line.
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Interrupt Process (IP) - Suspends, interrupts, aborts, or terminates the process to which the Virtual Terminal is connected. For example, if a user started a program on the Telnet server via the VTY, he or she could send an IP command to stop the program.
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While the Telnet protocol supports user authentication, it does not support the transport of encrypted data. All data exchanged during a Telnet sessions is transported as plain text across the network. This means that the data can be intercepted and easily understood.
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If security is a concern, the Secure Shell (SSH) protocol offers an alternate and secure method for server access. SSH provides the structure for secure remote login and other secure network services. It also provides stronger authentication than Telnet and supports the transport of session data using encryption. As a best practice, network professionals should always use SSH in place of Telnet, whenever possible.
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Later in this course, we will use Telnet and SSH to access and configure network devices over the lab network.
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The Application layer is responsible for directly accessing the underlying processes that manage and deliver communication to the human network. This layer serves as the source and destination of communications across data networks.
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The Application layer applications, protocols, and services enable users to interact with the data network in a way that is meaningful and effective.
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Applications are computer programs with which the user interacts and which initiate the data transfer process at the user's request.
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Services are background programs that provide the connection between the Application layer and the lower layers of the networking model.
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Protocols provide a structure of agreed-upon rules and processes that ensure services running on one particular device can send and receive data from a range of different network devices.
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Delivery of data over the network can be requested from a server by a client, or between devices that operate in a peer-to-peer arrangement, where the client/server relationship is established according to which device is the source and destination at that time. Messages are exchanged between the Application layer services at each end device in accordance with the protocol specifications to establish and use these relationships.
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Protocols like HTTP, for example, support the delivery of web pages to end devices. SMTP/POP protocols support sending and receiving e-mail. SMB enables users to share files. DNS resolves the human legible names used to refer to network resources into numeric addresses usable by the network.
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The Application layer is responsible for directly accessing the underlying processes that manage and deliver communication to the human network. This layer serves as the source and destination of communications across data networks.
​
The Application layer applications, protocols, and services enable users to interact with the data network in a way that is meaningful and effective.
​
Applications are computer programs with which the user interacts and which initiate the data transfer process at the user's request.
​
Services are background programs that provide the connection between the Application layer and the lower layers of the networking model.
​
Protocols provide a structure of agreed-upon rules and processes that ensure services running on one particular device can send and receive data from a range of different network devices.
​
Delivery of data over the network can be requested from a server by a client, or between devices that operate in a peer-to-peer arrangement, where the client/server relationship is established according to which device is the source and destination at that time. Messages are exchanged between the Application layer services at each end device in accordance with the protocol specifications to establish and use these relationships.
​
Protocols like HTTP, for example, support the delivery of web pages to end devices. SMTP/POP protocols support sending and receiving e-mail. SMB enables users to share files. DNS resolves the human legible names used to refer to network resources into numeric addresses usable by the network..

What is Nmap?

I use nmap for port scanning. I also use nmap to detect what services are running. Nmap is easy to use once you get the syntax down. Nmap was created by Fyodor. I plan to upload some videos to Youtube thus year to show how to use nmap. Here is a description from the nmap website.

Nmap ("Network Mapper") is a free and open source (license) utility for network exploration or security auditing. Many systems and network administrators also find it useful for tasks such as network inventory, managing service upgrade schedules, and monitoring host or service uptime. Nmap uses raw IP packets in novel ways to determine what hosts are available on the network, what services (application name and version) those hosts are offering, what operating systems (and OS versions) they are running, what type of packet filters/firewalls are in use, and dozens of other characteristics. It was designed to rapidly scan large networks, but works fine against single hosts. Nmap runs on all major computer operating systems, and official binary packages are avalable for Linux, Windows, and Mac OS X. In addition to the classic command-line Nmap executable, the Nmap suite includes an advanced GUI and results viewer (Zenmap), a flexible data transfer, redirection, and debugging tool (Ncat), and a utility for comparing scan results (Ndiff).

Nmap was named “Security Product of the Year” by Linux Journal, Info World, LinuxQuestions.Org, and Codetalker Digest. It was even featured in eight movies, including The Matrix Reloaded, Die Hard 4, and The Bourne Ultimatum.

What is Tor?

Tor is a network of virtual tunnels that allows people and groups to improve their privacy and security on the Internet. It also enables software developers to create new communication tools with built-in privacy features. Tor provides the foundation for a range of applications that allow organizations and individuals to share information over public networks without compromising their privacy.

Tor can also be used when penetration testing. Tor can use multiple proxies to hide your source address. there are plugins for Firefox. This tool is as easy to use as clicking a button.

Command Line Kung Fu

I came across a blog today that I thought was interesting. I'm always looking for ways to be more productive in a shell. I use Bash for most Linux commands.

Wireshark protocol analysis

I use Wireshark for packet analysis. I use this in my CCNA class and with clients. Wireshark can analyze hundreds of protocols. The Wireshark interface is simple to use. It can follow TCP streams. This is usefull for grabbing passwords that are not encrypted.

Backtrack

I use Backtrack for penetration testing. it has most of the tools I need. For anyone interested in security assesments feel free to email me.

Playing with Scappy.

Scapy is a powerful interactive packet manipulation program. It is able to forge or decode packets of a wide number of protocols, send them on the wire, capture them, match requests and replies, and much more. It can easily handle most classical tasks like scanning, tracerouting, probing, unit tests, attacks or network discovery (it can replace hping, 85% of nmap, arpspoof, arp-sk, arping, tcpdump, tethereal, p0f, etc.). It also performs very well at a lot of other specific tasks that most other tools can't handle, like sending invalid frames, injecting your own 802.11 frames, combining technics (VLAN hopping+ARP cache poisoning, VOIP decoding on WEP encrypted channel, ...), etc. See interactive tutorial and the quick demo: an interactive session (some examples may be outdated).

The text above was copied from the Scappy website.

I like the fact that I can manipulate packets with this program.

Nikto

Hello world. It's 2011. Things are going good. I have been studying penetration testing. I'm currently enrolled in college studying for my CCNA. I will be posting my notes on this blog.

Nikto is a web vulnerabilty scanner.

Nikto is an Open Source (GPL) web server scanner which performs comprehensive tests against web servers for multiple items, including over 6400 potentially dangerous files/CGIs, checks for outdated versions of over 1000 servers, and version specific problems on over 270 servers. It also checks for server configuration items such as the presence of multiple index files, HTTP server options, and will attempt to identify installed web servers and software. Scan items and plugins are frequently updated and can be automatically updated.

Update

I cannot beleive it has been a year since I posted last. I have a new son Jeremiah.My son Alexander is getting big.
I'm trying to network as much as possible. I'm on Facebook and Linkedin. I'm looking for clients that need managed security services and remote support. Phuture Networks now has a associate that can instal VoIP solutions to your small business.

Things on my mind today

I went to a job fair. It was basically a waste of time. Every company wanted you to apply online. I'm already doing that. I do everything online. I read about several technologies, games, and toys today at the library. I went to learn more about NAS or network attached storage and RAID levels. I feel these are fundamental skills to know. I also want to increase my reasoning and logical abilities so Im going to start playing more puzzles. I read about KENKEN a math game, unlike Sudoku you do math. I also read about game theory and how it ties to everything. I read about a article about cryptoanalyst in Wired. It talked about the CIA and Langley. It was a good article.

TGIF

It's Friday about 11:00AM. I just got done washing dishes, how exciting. I'm excited about going to work. I really like my job. I will be working on the website today. I have a ton of ideas to get some more traffic. If any one needs any help with computer consulting or repair in the Orange County area give me a call.