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The Command Line Part 3 -
Networking and TCP/IP Tools
The Command Line Part 1
The Command Line Part 2
The Command Line Part 3
The Command Line Part 4
The command line or command window has
many tools available for diagnostics and just for gathering
information about your systems current networking environment.
ipconfig
- Windows IP Configuration
This command gathers information concerning your current network
parameters for your network. Below are its parameters.
Usually when I am asked to diagnose a
problem the first thing I need to see is the current setup for the
PC. So I always issue the command ipconfig
/all It tells me how many adaptors I am working with
and their current configuration. Most likely you will be concerned
with your "Local Area Connection".
Next in my effort to diagnose an issue
I inevitably will try to ping
someone. Below are the command line switches for ping.
Ping
sends out a packet to a designated internet host or network computer
and measures its response time. This way you can look for
dropped packets, a slow line, or
o connection at all where there should be.
My favorite command when troubleshooting is
ping -n 100 -l 1500 "ip
address" or ping 216.109.112.135 -t
( Yahoo.com )
The 1st command floods the network with
1500 packets and will ping the host 100 times and then stop.
The -t option will ping the ip address
forever until you stop it. Ctrl-C to stop the ping.
Next is Tracert
Tracert shows the actual path between
two computers on the Internet. This path is not a straight line but
consists of numerous segments or "hops" from one intermediate
computer to another. Tracert shows each step of the
path taken. Consequently if you have a broken network with this
command you can see exactly how far the packets travel down the line
before they stop. Great troubleshooting tool!
Here's the tracert command in action.
Tracing my packets to Yahoo.com.
Another command which is a combination of ping and
tracert is pathping
Pathping will first
list the number of hops required to reach the address you are
testing and then send multiple pings to each router between
you and the destination. After
that, it computes results based on the packets returned from each
router.
Here's the results of my PathPing to
Yahoo.
Another very popular command with admin
troubleshooters is Netstat -
Displays active TCP connections
on your computer. Netstat
displays the active TCP connections and ports on which the computer
is listening, Ethernet statistics, the IP routing table,
statistics for the IP, ICMP,
TCP, and UDP protocols
Netstat commands are issued as
follows: netstat -ano Play with all the parameters to
see the different results. Can come in handy when troubleshooting
your network or looking for spyware. Usually spyware keeps an open
TCP/IP port on your PC.
A handy command sometimes is the
nslookup command. Let's
say on your network you know someone's ip address but not their dns
server name.
Below we see that when I issue the
nslookup command for 216.109.112.135 it yields the name Yahoo
What if you wanted to know your own dns
server name or hostname. Use the hostname command as shown below. As
you can see I named my box Core2Duo
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