Did someone say beer?

This is a fun site to poke around on and you might just learn how to do something to.

99 Bottles of Beer

Some basic network troubleshooting

From time to time you may need to troubleshoot a variety of network connectivity problems. Here are a few commands you can run from any Windows XP box and a brief description of each along with some of the switches I commonly find myself using. As usual, you can get a complete list of options for each of these by following the command with /?.

ARP – The address resolution protocol (ARP) maps an IP address to a physical address.

“arp -a” - Will display all of the entries currently listed in your arp table.

PING – Packet InterNet Grouper (PING) is used to verify connection to another computer.

“ping -t” - Will ping a device continually until interrupted.

TRACERT – Can be used to determine the router your packets take to get to a device on another network.

“tracert -d” - If your not interested in the host names of devices along the way

NETSTAT – Will show you the current ports and connections in use on your computer.

“netstat -a” - Shows all listening ports and server connections
“netstat -r” - Shows the contents of the routing table

NBTSTAT – Displays TCP/IP information using NetBIOS over TCP/IP

“nbtstat -a” - if you have an ip address this command will give you the remote netbios name
“nbtstat -n” - displays the local netbios name

These are just some tools already at your disposal for some quick troubleshooting. Please take the time to look over some of the other options available with these commands as some of them have quite a few options availble.


Some Basic Network Troubleshooting by scbowen is licensed under a Creative Commons Attribution-Share Alike 3.0 United States License.

How to license?

Have you ever wondered how to license something you have created? A good place to start is the Creative Commons website. This site will give you an explanation of the various licenses as well as a tool to help you decide which license is best for you.

Creative Commons

Entertainment

This site is rather entertaining and the open dialog can be witty at times.

Cranky Geeks

It's about choices

Have you ever wondered if there was an open source solution to that application your using? Well, here is a site that can help you out. While I am sure if you look around you can find alternatives not listed here, it is a good starting point for people beginning to explore for alternatives to the closed source applications they are currently using.

osalt.com

Cheat sheet anyone?

I ran across this nice little chart that showing the equivalent commands between DOS and Linux.

DOS and Linux

Because I like free learning

Because I like free learning sites myself, I try to share them with everyone else when I find one.

HP Learning

OSI and the story of the Seven Layers

By now you have probably heard of the seven layers of the OSI model, but maybe you’re unsure of what they are or the purpose of their being. This is just a short document to help you gain a basic understanding of the seven layers, what they are, and what they do.

The International Standards Organization (ISO), defines the seven different network layers through the Open Systems Interconnection (OSI) model. The purpose of this model is to define the means by which information gets from a client side application down to the physical cabling, across the wire, and back up to the application on the receiving side.

The listing of the seven layers is most often shown in a top down approach with layer seven being at the top, so I chose to display it this way as well.

Application

Presentation

Session

Transport

Network

Data-Link

Physical

So what does this mean exactly? The following is just a brief description of each of the seven layers.

Layer 1 – Physical

Physical medium such as twisted-pair, fiber optics, and wireless, as well how the data should be encoded at the bit level are defined as part of the physical layer.

An example of physical layer device is a hub or a repeater.

Layer 2 – Data-Link

This layer is responsible for transmission, flow control and error detection and is broken into two sub layers, the Logical Link Control (LLC) and the Media Access Control (MAC). The LLC is the interface between the upper layers and the physical media, while the MAC layer encapsulates the data into the appropriate format for use on the physical medium.

Layer 3 – Network

The network layer maps logical addresses to MAC-layer addresses and is responsible for ensuring that the packet is correctly routed to its destination. The Internet Protocol (IP) is an example of a network layer protocol.

Layer 4 – Transport

There are a lot of things happening at the transport layer. This is where large data streams are broken down into smaller packets if necessary and sequencing is applied to ensure all of the data makes it to the final destination. This is also the layer at which packet size is determined based on the network architecture being used. Things like error recognition, error recovery, and acknowledgements also occur at the transport layer.

Layer 5 – Session

The session layer is responsible for setting up, maintaining, and tearing down sessions between two applications over the network. Regulating data flow and determining and monitoring the service type are also controlled at the session layer.

Layer 6 – Presentation

Things like data compression, encryption, and translation of file types occur at the presentation layer.

Layer 7 – Application

These are the actually applications that are used. Applications such as email, ftp, http, etc… all exist in the application layer.

As I stated, this is just a brief over view of the seven layers of the OSI model. Hopefully this gives whoever reads it a little better understanding of happened when you visited this site.

OSI and the story of the seven layers by scbowen is licensed under a Creative Commons Attribution-Share Alike 3.0 United States License.

Online Video

I am really addicted to this site these days. It has a good mix of genres as well as older and newer content. Whether you like television programs or movies, you will probably find something here you like.

Hulu

This is no dinosaur

This is everything a performance hard drive should be, fast, high capacity, efficient, and supported by a good warranty.

Western Digital Drive