Windows Command Line

DOS? Command Line? Where are the Icons?

Type in a command and hit [Enter]
How do you get started....
IP address
Telnet
Trace Route
Ping
Path Ping
NS Lookup
Netstat

Mac Users

Go to APPLICATIONS, look for TERMINAL. Open the terminal program.

Windows Users

The shortcut is to use the keyboard. This is useful for individuals using Vista because often the "Run" command has been removed from the start menu.
2 keys are invloved. Hold down the [R] and the [windows logo] Keys.
If you want to access the command prompt from the start menu....

Choose the program RUN


Type in cmd


This is what a command line prompt looks like

IP Config

Your IP address is: 38.107.179.240

Typing in the command ipconfig will tell you what your computer's IP address is. ipconfig /all provides even more information.
There are many times when you need to get a different IP address. For example, if the IP address assigned to you by your internet service provider is blacklisted.
To drop your current IP address, type in: ipconfig /release.
To get a new IP address, type in: ipconfig /renew.

Telnet

Typing in the command telnet "domain name" port# allows you to make a connection to a specific port.
In this exmaple, telnet mysiteisdown.com 110 we are making a connection to the incoming mail server port- port #110
Many Internet Service Providers, Firewalls, and Anti-virus systems block the use of telnet.

To view the commands associated with telnet, type in the command telnet

At the next prompt type in a ?

Running a Trace

Typing in the command tracert "domain name" or for MAC users, traceroute "domain name" the computer will provide a list of all the IP addresses it goes through from the computer you on before reaching it's destination. This can be helpful because if the request times out, you can see where it stopped. This may mean that there is a router out on the internet. It also provides you with information about how long it took to move through the path.

This is what a request timed out might look like. In this example, we never even make it to the router for our Internet Service Provider. This means there is a problem with the internet connection we have. Either there is no signal or we need to start troubleshooting.

If a website has a subdomain pointing to a different IP address, running a trace route with the subdomain portion will provide a different result. (www is a subdomain, anything to the left of the domain name itself is a subdomain.) This example shows that google.com and www.google.com do not actually go to the same servers. They go to different IP addresses, and www.google.com redirects to www.1.google.com.

Ping

Typing in the command ping "domain name" will send a data packet from the computer you are on, to the computer where the domain information is located. It will tell you the IP address where the domain is located and tell you if there is informational loss along the route. This may happen if a website sometimes shows up, but not every time, or only part of the website is showing up. The information could be lost in many different ways: bad internet signal, DNS propagation hasn't finished, server overload, router issues....

Path Ping

Typing in the command pathping "domain name" will provide a truncated version of trace route.

NS Lookup

Typing in the command nslookup will give a new prompt where you can then type in the domain name. The system will tell you what the name server IP is.

You can also get more specific information by setting a query type. set query=any will provide all the information such as the name servers, the IP address, the MX records, the SOA record information...
You can also run an NS lookup by typing in nslookup -q=”record type” “domain name” if you want information about a specific DNS record.

netstat

Typing in the command netstat -an will show you what is open on your computer.
Proto is the protocol being used.
Local Addresss is the open address on your computer.
Foreign Address is the address you are connected to.
State tells if the address is open, closed, or connected.
This system uses IPv4. This means the IP address appears as an octet, (123.45.67.890). A system using IPv6 will look like this: 2003:1df8:0:8a2e:85a3:9hf8:7433.
The open ports are listed in the TCP section. You can see the IP address, followed by the port number. 0.0.0.0:PORT#. If the far right hand side, state, shows listening or established, these are open ports on your computer.