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Showing posts from February, 2012

Tools for understanding and troubleshooting TCP – IP

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Tools for understanding and troubleshooting TCP – IP TCP – IP has tools built in, as a rule, in any operating system. They are utility programs, but are referred to as protocols. These include: ping arp ipconfig tracert ( traceroute in Linux ) These protocols are run from the command prompt in Windows. One way to get to a command prompt: Windows logo Run cmd.exe You can find out more about these protocols by appending /? to the name ping: ping /? returns this: ping sends a request for a response to a network device. If the device is configured to respond, ping tells you how long it took to make the round trip. This is the result of a ping to the IP address of google: You can also ping URLs: If you can ping an IP but not the associated URL, you have a DNS problem. If you want to ping non stop until the device responds, add a -t between ping and the IP address: ping -t 74.125.95.99 To pause this continuous ping:  CTRL-Break To terminate this continuous ping:  CTRL-C arp:

Basic Network Troubleshooting

Things you need to know before you can ask an intelligent question correctly: Every beginner who comes here asks questions without providing the information necessary to answer that question. If you read and understand this tutorial, you will know how to ask a question properly. But you may not need to, because you may find the solution to your problem here. Definitions: LAN:  Local Area Network. Your local network WAN:  Wide Area Network. The larger network your LAN connects to. The first step on the path to the Internet. DHCP:  Dynamic Host Configuration Protocol. A server that assigns IP Address, Subnet Mask, Default Gateway and DNS Server values to your TCP-IP system. DNS:  Domain Name System. DNS is what translates the Google URL into googles IP address. Like an automated phone book. Router:  A network device with two interfaces; one side WAN, the other side LAN. They must be on different networks, or there is nothing for the router to do. The router inspects network taffic