Monday, May 24, 2010

What Is My IP Address

Internet Protocol Address:

This number is an exclusive number all information technology devices (printers, routers, modems, et al) use which identifies and allows them the ability to communicate with each other on a computer network. There is a standard of communication which is called an Internet Protocol standard (IP). In laymans terms it is the same as your home address. In order for you to receive snail mail at home the sending party must have your correct mailing address (IP address) in your town (network) or you do not receive bills, pizza coupons or your tax refund. The same is true for all equipment on the internet. Without this specific address, information cannot be received. IP addresses may either be assigned permanently for an Email server/Business server or a permanent home resident or temporarily, from a pool of available addresses (first come first serve) from your Internet Service Provider. A permanent number may not be available in all areas and may cost extra so be sure to ask your ISP.

Domain Name System (DNS): 

This allows the IP address to be translated to words. It is much easier for us to remember a word than a series of numbers. The same is true for email addresses.

For example, it is much easier for you to remember a web address name such as whatismyip.com than it is to remember 192.168.1.1 or in the case of email it is much easier to remember email@somedomain.com than email@192.168.1.1

Dynamic IP: 

One that is not static and could change at any time. This type of IP is issued to you from a pool of IP addresses allocated by your ISP or DHCP Server. This is for a large number of customers that do not require the same IP all the time for a variety of reasons. Your computer will automatically get this number as it logs on to the network and saves you the trouble of having to know details regarding the specific network configurations. This number can be assigned to anyone using a dial-up connection, Wireless and High Speed Internet connections. If you need to run your own email server or web server, it would be best to have a static IP.

Static IP: 

One that is fixed and never changes. This is in contrast to a dynamic IP which may change at any time. Most ISP's a single static IP or a block of static IP's for a few extra bucks a month.

IP version 4: 

Currently used by most network devices. However, with more and more computers accessing the internet, IPv4 IPs are running out quickly. Just like in a city, addresses have to be created for new neighborhoods but, if your neighborhood gets too large, you will have to come up with an entire new pool of addresses. IPv4 is limited to 4,294,967,296 IPs.

IP version 5: 

This is an experimental protocol for UNIX based systems. In keeping with standard UNIX (a computer Operating System) release conventions, all odd-numbered versions are considered experimental. It was never intended to be used by the general public.

IP version 6: 

The replacement for the aging IPv4. The estimated number of unique IPs for IPv6 is 340,282,366,920,938,463,463,374,607,431,768,211,456 or 2^128.

The old and current standard of IPs was this: 192.168.100.100 the new way can be written different ways but means the same and are all valid:

  • 1080:0000:0000:0000:0000:0034:0000:417A
  • 1080:0:0:0:0:34:0:417A
  • 1080::34:0:417A

Read more: http://www.whatismyip.com/#ixzz0opZFZYsI

Friday, May 21, 2010

Router Commands Overview

Router Commands Overview

In this section you will learn about the router commands, configurations, privileged mode commands, routing protocols, cisco labs and network configurations.

There are hundreds of basic and advance level commands of a router. It is not easy to remember all the commands. But some commands are frequently used and can be remembered with some practice. I have provided a list of the most commonly used commands based on their features and usage.


You will find here some basic terminology of a router.

Routing: Routing is a process of moving the data (packets) through an inter network. Routing performs the two basic tasks. Define the paths for a packet and then forward the packets on the basis of defined paths. Routing can also be defined as the communication between two or more logically and physical networks and this communication (packet transfer) is brought by a router.



First of all you should remember the keyboard shortcuts of a router.

Keyboard Shortcuts

CTRL-N - show next command
CTRL-P - show previous command
SHIFT-CTRL-6 – Break

Configuring the Router

You will be able to learn the basic commands for configuring a router.

sh running-config - details the running configuration file (RAM)
sh startup-config - displays the configuration stored in NVRAM
setup - Will start the the automatic setup; the same as when you first boot the router
config t - use to execute configuration commands from the terminal
config mem - executes configuration commands stored in NVRAM; copies startup-config to running-config
config net - used to retrieve configuration info from a TFTP server
copy running-config startup-config - copies saved config in running config (RAM) to NVRAM or "write memory" for IOS under ver.11
copy startup-config running-config - copies from non-volatile (NVRAM) to current running config (RAM)
boot system flash - tells router which IOS file in flash to boot from
boot system tftp - tells router which IOS file on the tftp server to boot from
boot system rom - tell router to boot from ROM at next boot
copy flash tftp - Copies flash to tftp server
copy tftp flash - Restores flash from tftp server
copy run tftp - Copies the current running-config to tftp server
copy tftp run - Restores the running-config from tftp server

General Commands

Here is a list of the general commands. These are the basic level commands and most commonly used
no shutdown - (enables the interface)
reload - restarts the router
sh ver - Cisco IOS version, uptime of router, how the router started, where system was loaded from, the interfaces the POST found, and the configuration register
sh clock - shows date and time on router
sh history - shows the history of your commands
sh debug - shows all debugging that is currently enabled
no debug all - turns off all debugging
sh users - shows users connected to router
sh protocols - shows which protocols are configured
banner motd # Your customized message here # - Set/change banner
hostname - use to configure the hostname of the router
clear counters - clear interface counters

Privileged Mode commands of a router

Learn how to work in the privileged mode of a router.
enable - get to privileged mode
disable - get to user mode
enable password - sets privileged mode password
enable secret - sets encrypted privileged mode password
Setting Passwords on router
Here you will be able to learn how to set the password on a router.
enable secret - set encrypted password for privileged access
enable password - set password for privileged access (used when there is no enable secret and when using older software)
Setting the password for console access:
(config)#line console 0
(config-line)#login
(config-line)#password
Set password for virtual terminal (telnet) access (password must be set to access router through telnet):
(config)#line vty 0 4
(config-line)#login
(config-line)#password
Set password for auxiliary (modem) access:
(config)#line aux 0
(config-line)#login
(config-line)#password

Router Processes & Statistics


By these command you can see the statistics and different processes of the router.
sh processes - shows active processes running on router
sh process cpu - shows cpu statistics
sh mem - shows memory statistics
sh flash - describes the flash memory and displays the size of files and the amount of free flash memory
sh buffers - displays statistics for router buffer pools; shows the size of the Small, Middle, Big, Very Big, Large and Huge Buffers
sh stacks - shows reason for last reboot, monitors the stack use of processes and interrupts routines

IP Commands

Here is a list of the IP Commands
Configure IP on an interface:
int serial 0
ip address 157.89.1.3 255.255.0.0
int eth 0
ip address 2008.1.1.4 255.255.255.0

Other IP Commands:

sh ip route - view ip routing table
ip route [administrative_distance] - configure a static IP route
ip route 0.0.0.0 0.0.0.0 - sets default gateway
ip classless - use with static routing to allow packets destined for unrecognized subnets to use the best possible route
sh arp - view arp cache; shows MAC address of connected routers
ip address 2.2.2.2 255.255.255.0 secondary - configure a 2nd ip address on an interface
sh ip protocol

CDP Commands (Cisco Discovery Protocol uses layer 2 multicast over a SNAP-capable link to send data):

sh cdp neighbor - shows directly connected neighbors
sh cdp int - shows which interfaces are running CDP
sh cdp int eth 0/0 - show CDP info for specific interface
sh cdp entry - shows CDP neighbor detail
cdp timer 120 - change how often CDP info is sent (default cdp timer is 60)
cp holdtime 240 - how long to wait before removing a CDP neighbor (default CDP holdtime is 180)
sh cdp run - shows if CDP turned on
no cdp run - turns off CDP for entire router (global config)
no cdp enable - turns off CDP on specific interface

IPX Commands

Enable IPX on router:
ipx routing
Configure IPX + IPX-RIP on an int:
int ser 0
ipx network 4A

Other Commands:

sh ipx route - shows IPX routing table
sh ipx int e0 - shows ipx address on int
sh ipx servers - shows SAP table
sh ipx traffic - view traffic statistics
debug ipx routing activity - debugs IPS RIP packets
debug ipx sap - debugs SAP packets

Routing Protocols

RIP, IGPR and OSPF are the routing protocols and here is a list of the commands for the working on the routing protocols.
Configure RIP:
router rip
network 157.89.0.0
network 208.1.1.0

Other RIP Commands:
debug ip rip - view RIP debugging info

Configure IGRP:
router IGRP 200
network 157.89.0.0
network 208.1.1.0

Other IGRP Commands:
debug ip igrp events - view IGRP debugging info
debug ip igrp transactions - view IGRP debugging info

Access Lists
Here is a list of the Access list command of a router.
sh ip int ser 0 - use to view which IP access lists are applies to which int
sh ipx int ser 0 - use to view which IPX access lists are applies to which int
sh appletalk int ser 0 - use to view which AppleTalk access lists are applies to which int

View access lists:
sh access-lists
sh ip access-lists
sh ipx access-lists
sh appletalk access-lists

Apply standard IP access list to int eth 0:
access-list 1 deny 200.1.1.0 0.0.0.255
access-list 1 permit any
int eth 0
ip access-group 1 in

Apply Extended IP access list to int eth 0:
access-list 100 deny tcp host 1.1.1.1 host 2.2.2.2 eq 23
access-list 100 deny tcp 3.3.3.0 0.0.0.255 any eq 80
int eth 0
ip access-group 100 out

Apply Standard IPX access list to int eth 0:
access-list 800 deny 7a 8000
access-list 800 permit -1
int eth 0
ipx access-group 800 out

Apply Standard IPX access list to int eth 0:
access-list 900 deny sap any 3378 -1
access-list 900 permit sap any all -1
int eth 0
ipx access-group 900 out

WAN Configurations Commands


Networking over WAN is the main functionality of a router. The most common use of a router is for the WAN connectivity. Here is a list of the commands for the different methods of the WAN connectivity.

PPP Configuration

Point to point protocol is a method for the WAN connectivity and you will find here some commands of PPP.
encapsulation pppppp authentication
ppp chap hostname
ppp pap sent-username
sh int ser 0 - use to view encapsulation on the interface

Frame-Relay Configuration

One of the methods for the WAN connectivity is the Frame Relay. Find here some basic commands for the WAN connectivity through Frame Relay.
encapsulation frame-relay ietf - use IETF when setting up a frame-relay network between a Ciscorouter and a non-Cisco router
frame-relay lmi-type ansi - LMI types are Cisco, ANSI, Q933A; Cisco is the default; LMI type is auto-sensed in IOS v11.2 and up
frame-relay map ip 3.3.3.3 100 broadcast - if inverse ARP won't work, map Other IP to Your DLCI # (local)
keep alive 10 - use to set keep alive
sh int ser 0 - use to show DLCI, LMI, and encapsulation info
sh frame-relay pvc - shows the configured DLCI's; shows PVC traffic stats
sh frame-relay map - shows route mapssh frame-relay lmi - shows LMI info

Miscellaneous Commands

In the last but not least here is a list of the some miscellaneous and useful commands
sh controller t1 - shows status of T1 lines
sh controller serial 1 - use to determine if DCE or DTE device
(config-if)#clock rate 6400 - set clock on DCE (bits per second)
(config-if)#bandwidth 64 - set bandwidth (kilobits)

What is Ethernet ?

What is Ethernet ?

In this section you will learn about the lan terminology, basic ethernet networking overview, a general introduction to LAN, introduction to IEEE, lan topologies, wan standards. You can also find these categories in this site such as network tutorials, computer networking guide, what is networking, tech study guides, topologies, what is data recovery, wireless communication, computer interview questions and network certification. The IEEE standards have been developed by the International Standards Organization (ISO). The Institute of Electrical and Electronic Engineers (IEEE) in 1985 produced a series of standards for the Local Area Networks, which are called IEEE 802 standards.

These standards have been accepted widely throughout the IT world. One of the IEEE 802 standards, the IEEE 802.3 is known as “Ethernet”. Ethernet is the most widely used LAN technology. Ethernet was developed by Xerox corporations in 1972 and it was the first LAN.

According to the ISO standards allows manufactures to produce the devices and equipments, which are guaranteed to operate anywhere.

The Ethernet in its simplest form uses a passive bus that operates at 10 Mbps. The bus is formed from the co-axial cable, which connects all the PCs in the LAN.

A single LAN may have 1024 attached computers, although in the real practice most LANS have fewer computers than this number. One or more segments of the co-axial cable are attached to end to end to create the Ethernet Cable Segment. Each segment is terminated by 50 ohm resistors.


In today’s IT world the reliable and timely access to the information has become vital. Today coworkers thousands of miles apart from each other can share data, voice, video etc with the fractions of seconds. Similarly a larger number of the coworkers can review the research data simultaneously. The Internet allows businesses to share information and resources with their customers.

Ethernet is a communication protocol that is embedded in software and hardware devices that intended. Ethernet has become the standard computer networking protocol with the help of the Xerox, Intel and Digital

A basic LAN consists of the following components.

  • Two or more computers.
  • Network Interface card or LAN Card in each PC.
  • Ethernet cable (Cat5, UTP/SPT) cable to connect the two computers.
  • A hub, switch or router to route or direct the network traffic.
  • Software for the communication/computer networking.

A network interface card (NIC) is attached and installed in each PC and is assigned a unique address. An Ethernet cable is used to connect two computers; Ethernet cable has RJ45connectors at both ends. There can be two scenarios 1. Two computers can directly connect with each other or 2. Each computer is directly connected with the hub/switch and hence communication occurs in the network. The hub or switch acts as relay.

Computer Network can be wireless. Despite of using Ethernet cable for the communication, Wireless Network Interface cards use radio waves to communicate with the wireless switch or hub. A small antenna is used in the wireless NICs, switches and hubs. Although the wireless networks are more easy to use as compared to the cabled networks, but more configurations and extra care is required to setup and run a wireless network.

The alternate technologies to Ethernet are “Token Ring”, which is used in the Ring Topologiesnetworks. Token Ring is designed by the IBM and ATM. In ATM networking, devices are connected with each other over a very large distance (thus forms the WAN), and behaves like LANs.

Ethernet is a well established and widely used network standard for small to medium sized Ethernet networks as well as for other networks. Ethernet has been used over the 3 decades and forms a very excellent networking/communication environment.

Ethernet Terms

Ethernet follows a simple set of rules. To understand these rules its important to understand the following terminology.

  • Node – The devices that are attached to the segments are nodes.
  • Frame – The nodes (computers or network devices) communicates in the form of short messages that are known as frames. The frames are chunks of information with variable size.
  • Segment – A single shared medium is known as a Ethernet segment.
  • Medium – The Ethernet devices are attached to a common medium. The frames of the data travel along with that medium. This medium can be coaxial cable. Today most commonly used communication mediums are UTP/STP cable, fiber optic cables.

Frames are analogous in human language. We have some rules for constructed the sentences. The Ethernet protocol specifies a set of rules for constructing the frames. The frames length varies. Each frame must contain source and destination address for the identification of the recipient and the send of the message. The nodes can be uniquely and easily identified. Each Ethernet devices must have a single unique address.

Compute networking standards has brought a revolution in the network computing and it made the communication very easy and standarized. Now every computer and networking devices has to to follow the same standard to communicate with each other.

Microsoft Certifications

Microsoft 

MCSE

Microsoft Certified Systems Engineer (MCSE) is designed for the professionals who are some requirements of analyzing the business, designing, making infrastructure, and implementing the securities at certain levels. MCSE is based on the Microsoft Windows 2000 platform and Windows NT platform (though many of the NT exams have been obsolete now). The Windows 2003 server has been merged into the MCSE exam.

MCSE certification does not retire but the newer versions are released by the Microsoft after few years. So the candidate has to be upgraded himself/herself with these latest exams. There are no specific requirements for the MCSE certifications. Those candidates who have one year experience in managing a computer network, network or desktop operating systems, will be considered suitable for this exam. Job descriptions and roles including after achieving the MCSE are Systems engineer, Network Engineer, Network Consultant, and Systems Analyst.

There is a 7 exams pass requirement for this certification and the candidates how are holding the MCSE 2000, are required to give 2-upgrade exams. By passing these exams you can achieve Windows Server 2000 MCSE exam.

Introduction to the Network Communication Devices

Introduction to the Network Communication Devices

In this tutorial you will learn get the basic introduction to network devices such as nic adapters, routers, hubs, switches, modems, communication cables, lan/wan routers, gateway and other devices. A network is consists of a larger number of the communication devices. The simplest device that is used in the communication is the NIC adapter which is attached with the every computer in a network. If you want to build a LAN, you will need to have computers, hubs, switches, network adapters, UTP/STP cables, routers, internal/external modems, connectors, cable testers and clipping tool.

On the other hand if you need to build WAN, you will need to have routers, switches, dedicated or leased telephone lines such as ISDN lines, frame relay connection and other types of wan communication connections.
There are different communication mediums such as Ethernet cables, copper wire, coaxial cable, fiber optic cables, leased telephone lines and ever air is also a communication medium for the satellite communication. The most common networking medium is the LAN is the Ethernet cable (UTP/STP), which is used in the star topology. Hub is a central device of a network and every computer in a network is directly connected with the hub.

If the hub fails to work, the communication between the computers stops till the hub again starts working. Hub broadcasts the data to its every port, and then finding the destined computer, the data sent toward it. The switch is an advance form of the hub similar in functions but the advanced switches has a switching table in them. A advanced switch stores the MAC address of every attached computer and the data is only sent to the destined computer, unlike the hubs where data is sent to all ports. A router is a key device in the internet communication and wan communication system. A router has software called routing table and the source and destination addresses are stored in the routing table.


A router connects two logically and physically different networks. Router finds the IP address of the next hop (next router) and the data is sent toward it and so on. The well known routers developing companies are Cisco systems, Nortel, DLink and others. Every ISP, banks, corporate offices and multinational companies use routers for LAN and WAN communications and communication in their private networks. A gateway can be device or software in a network.

A gateway device connects the LAN with the internet. A gateway is directly exposed to the internet so it should be securely configured and in and out traffic should be monitored. If you are using DSL connection, you must need a DSL modem in your network. The telephone line is connected with the DSL modem and UTP/STP cable attaches your computer with the DSL modem. Modems are the devices that are used to modulate and demodulate the data. They convert analogue signals to digital and digital signals to analogue so that signals can travel on the telephone lines.

There are certain types of the cables that are used to connect two or more computers in a network. Fiber optic cable acts as a backbone between the ISPs and corporate offices. Data travels at the speed of light on the fiber optic cables. The cost and the installation cost of the fiber optic cable is very high but it is becoming very popular in the home networking and LANs also. In the local area networking, 10baseT/CAT5 cable is most commonly in use.

A server is a computer in network that provides services to the client computers such as logon requests processing, files access and storage, internet access, printing access and many other types of services. Servers are mostly equipped with extra hardware such as plenty of external memory (RAM), more data store capacity (hard disks), high processing speed and other features.

How to Configure a Network?

How to Configure a Network?

In this section you will learn how to configure a network, peer to peer, client server, workstation, server, basic data communication.

Peer to Peer network model

Before configuring a computer network, you have to decide that, which networking model you require. There are two main types of network models. Peer to peer and client-server network model. In the peer to peer network model you simply use the same Workgroup for all the computers and a unique name for each computer.

Additionally, you will have to give a unique IP address of the same class A, B, or C for all the computers in your network and its related subnet mask e.g if you decide to use class A IP address for your three computers in your Peer to Peer network then your IP address/Subnet mask settings can be as follows.

Computer Name IP Address Subnet Mask Workgroup

PC1 100.100.100.1 255.0.0.0 Officenetwork
PC2 100.100.100.2 255.0.0.0 Officenetwork
PC3 100.100.100.3 255.0.0.0 Officenetwor

Please note that the above example is for only illustration purpose so you can choose any IP address, computer name and workgroup name of your interest.

For doing this right click on My Computer and then click Properties then go to the Network Identification section and set these.

In a peer to peer network all computers acts as a client because there is not centralized server. Peer to peer network is used where not security is required in the network.


If a computer fails to work then all other computers work normally in peer to peer network.

Client/Server Network Model

In the client/server network model a computer plays a centralized role and is known as a server all other computers in the network are known as clients. All client computers access the server simultaneously for files, database, docs, spreadsheets, web pages and resources like hard diver, printer, fax modem, CD/DVD ROM and others. In other words, all the client computes depends on the server and if server fails to respond or crash then networking/communication between the server and the client computes stops.

If you want to configure a client-server network model then first prepare the server. Install Windows 2000 or Windows 2003 Server from the CD on the server computer and make a domain. You can create a domain by this command on the Run “DCPROMO”. You can give this command once you install the server successfully. After you give the DCPROMO command you will be asked for a unique domain name. All the client computers will use the same unique domain name for becoming the part of this domain. This command will install the active directory on the server, DNS and other required things. A step by step wizard will run and will guide you for the rest of the steps. Make sure that a network cable is plugged in the LAN card of the server when you run the DCPROMO.exe command.

When the Active directory is properly installed on the server, restart the server. You can create network users on the server computer and also name/label the network resources like computers/printers etc.

Once you install the server successfully now come to the client computers. Install Windows 2000 professional on your all client computers. Once you install the Windows 2000 professional on the clients the next step is to make this computer (client computer) a part of the network.

Configuration Steps

1. Choose a unique name for each client computer
2. Choose unique IP address for each computer and relevant.
3. Use the same domain name for all client PCs.

Network/System administrators are required to do these administrative tasks on the server and client computers. Any shared resources on the network either on the server or the clients can be access through the My Network Places in the Windows 2000 platform. There is another way to connect to the shared resources by giving this command in the run \\ComputerName\SharedDriveLetter.

Network configurations steps can be implemented by right clicking the My Computer>Properties>

For giving the IP address you will have to right click on the My Network places>properties>Local Area Connection>Properties>Internet Protocols (TCP/IP)>Properties and then give the IP address and subnet mask of the same range and class for all the computers in the network.

If you are unable to configure your home network you may have to use an IT company such as this IT consulting Burlington Company.

Citrix Certifications

Citrix Certifications

Citrix CCA, CCEA and CCIA are among the hottest IT certifications. These certifications offer the knowledge of the Citrix products and technology. Citrix products allow to access the server based applications regardless of the operating system being used on the server side. Citrix Administrators are required to have the strong knowledge in the Windows based operating systems and the Citrix products. According to the Citrix website, 90% of the top 500 fortune companies are using the Citrix products.

These products provide the centralized management of the IT infrastructure and reduce the overall operational cost. The certifications are geared towards the IT professionals who want to deliver the application solutions in a complex IT environment and optimizing the performance of the WAN applications. Citrix offers the following certifications.

CCA (Citrix Certified Administrator)

CCA certification focuses on the knowledge and skills that are required for the implementation of the Citrix products in an existing network. CCA provides excellent skills to the network administrators and independent consultants. The CCA tracks includes Presentation Server 4, Access Gateway 4, Certified Administrator for Citrix NetScaler 8, Certified Administrator for EdgeSight 4, Certified Administrator for Citrix WANScaler 4, Certified Administrator for XenServer Enterprise Edition 4 and Certified Administrator for Password Manager 4.

CCSP (Citrix Certified Sales Professional)

CCSP certification certifies the sales professionals and it is geared towards the individuals who sell the Citrix products. Citrix certifies that you have the sound knowledge about its products. CCSP exam offers three separate tracks such as Windows Application Delivery, Web Application Delivery and Desktop Delivery.

CCEA (Citrix Certified Enterprise Administrator)

Attaining the CCEA certification is the next step to the CCA certification. You need to pass the four additional exams in order to get the CCEA status.

You must pass the following two exams:

1. Exam 910, Citrix Resource Management Services
2. Exam 950, Citrix Nfuse Administration

Then, you need to pass one of these two exams:

1. Exam 911, Citrix Resource Manager
2. Exam 921, Citrix Installation Manager

Finally, you must also pass one of these three exams:

1. Exam 920, Citrix Installation Management Services
2. Exam 930, Secure ICA and Security
3. Exam 940, Load Balancing Service

After passing the required exams, you status will be upgraded to a CCEA.

CCI (Citrix Certified Instructor)

CCI certification is designed for the individuals who have the good knowledge of the Citrix Access suite and the operating systems. In order to delivering the lectures at the Citrix certified institutes, you need to earn a CCI certification. The requirements of earning the CCI status includes attend the Citrix approved “Train the Trainer course”, you must hold a current certification in Windows NT, 2000 or Unix based on your plan to instruct on, attend the CCA course and pass the CCA exam with more than 80% marks and you will get the Citrix Certified Instructor status.

(CCIA) Citrix Certified Integration Architect

CCIA exam is designed for the individuals who are responsible for designing, analysis, and implementing Citrix technologies in the IT infrastructure of small to large organizations.