The ping command is the most widely used
of all network utilities. It's a tool that is used to test issues
such as network connectivity and name resolution. For example let's go
ahead and ping a host IP address. So at a command prompt you would type 'ping' space then the IP address, then press 'enter' Now it's going to send out 4 data
packets to the destination IP address we chose. Then the destination will send the data
packets back to us as a reply, and these replies are called echo reply requests. And these replies
will inform us about what's happening with the
destination host we pinged. For example if we received a reply, then
that means that there is general network connectivity between us and the destination, but if we did not get a reply, then that means that there is no reply
from a host and it could mean that there is no network connectivity between us. But if we pinged a host and we got a
message that says "request timed out", then that could mean
that the host is down or that it's blocking all ping requests. Or in another scenario, after we pinged, if we get a message that says
"destination host unreachable", then that message is coming from
the router, and it means that a route to the
destination cannot be found. The ping command can also be used to
test name resolution. For example, before we use the ping
command with an IP address, but we can also use it with a domain
name. For example, we could type 'ping' space then the domain name "yahoo.com". So by
pinging the domain name, if we get the same successful result as
type in the IP address then this would indicate that name
resolution by DNS is working fine. But let's just suppose that the domain name ping failed, then
next step will be typing the IP address instead. So if by typing in the IP address, if the
ping command was successful this time that we now know that we are having a
problem with DNS The ping command also be combined with other sub
commands call switches. Switches are used to alter the
parameters up the ping utility. You can view a full list at the switches
by typing "ping" space forward slash and then a question mark. Our next utility is called TRACERT,
which stands for trace route. This utility is used to see the exact
path the data packet is taking on its way to
the destination. So for example, let's go ahead and trace
the route from our computer to another computer. So
at a command prompt, we would type "tracert" space and then the IP address and press enter. Now the data packet will find its way to
the destination. And each time it reaches a router on its
path, it will report back information about
the router. Such as the IP address and the time it
took between each hop. So the TRACERT utility is a great tool
that can be used to pinpoint where a problem lies on a network if a data packet cannot
reach the destination. So for example if we try to ping a
destination and the pain command failed we can use
the TRACERT utility to find out where the
data packet is failing along its path. So let's go
ahead and trace route this IP again and let's suppose this time there
was a problem. So let's type in "TRACERT" and the IP
address. and as a data packet goes along its path,
it will tell us at which area the problem lies. And the data
packet stops in here. So the TRACERT utility has isolated that the problem is
somewhere between these two routers.
