Traveling Through a Network

 

Traveling Through a Network

    Information is created by you, the "computor", but what happens to that information when you send it to someone, or when you interact with a website or application?  Well, it's simple, or is it?  Once you hit send, information is condensed into smaller bits of information called packets, which are then sent in pieces as electrical pulses over your ethernet cable or radio waves via wi-fi, where it is sent through your network equipment such as switches, firewalls, and finally a router or modem.  From your router, the packets are sent to the address of the receiver's server or router where they decide whether the information is properly formatted to understand, while other equipment such as firewalls may first analyze the packets to determine if the files are safe and turn them away if it thinks there is something malicious embedded before allowing the packets to be sent through.  Once the router determines that it accepts the files being sent, it will shake hands with the sender's network and send a response back to the sender telling it that it's okay to send the data thus completing the file transfer.

    There are times when your data may not be sending, or network equipment may be down or flapping.  Two wonderful, easy to use tools for troubleshooting these issues are pings and traceroutes:

Pings

    A ping is an easy way to send packets to a device or website which will be returned by showing the success or failure of the completion of the ping and the speed or latency in which the device responds in milliseconds.  The ping command is very simple, simply hold windows button and press "R", then type cmd and hit enter, which will open a command window, type ping (space) then your ip address or DNS name associated with it.  In the example below we pinged 8.8.8.8 which is the address for Google and is a popular ping to troubleshoot internet connectivity on a computer.

    If a ping comes back successful, then your connection to the internet or device is likely to

be successful, if it comes back with request timed out or destination host unreachable, then 

there is some troubleshooting left to do.  Also, when troubleshooting a network device such 

as a wireless access point, you may choose to do a constant ping by adding a space after the 

ip or DNS and type -t, which will keep the ping going indefinitely until you type control 

"C" to end it.

 Traceroute (tracert)

     A traceroute is similar to a ping but is more in depth, while a ping sends and receives packets to incite a response from its destination, a traceroute measures where the packets are being sent, including switches, firewalls, routers, and servers on both ends to map where the packets are going through their destination.  Traceroute is a helpful tool if you are troubleshooting failure to a specific website or within your own network to find where the packets are being lost on their path, which will often lead you to which device is not sending the information through giving you a place to start your troubleshooting.  I recently used this method to find out why my Verizon cellular extenders were not connecting to our network.

    To run a traceroute you will simply follow the same path to your command window then instead of typing ping you will type tracert followed by a space and your desired ip address or DNS, you will then see all of the stops your packets make on their journey.  Don't let the request timeouts discourage you though as they are common in a tracert and can often be explained by your internet service provider dropping packets, or your packets being blocked in one place then redirected to another for a successful route.