Some routers and firewalls are configured to not pass ICMP Echo requests or echo reply requests, attackers
sometimes try to map out remote networks by pinging all the possible addresses and collecting replies.
So blocking this type of traffic at the perimeter is fairly common.
Just because you do not receive a reply to a ping does not necessarily mean that the host is not available.
Traceroute is a computer network diagnostic tool for displaying the route or path of packet's through
the Internet between your computer and a specified destination computer.
It also measures the amount of time each hop took.
When you run the utility, it initiates the sending of a packet, including in the packet, a TTL,
a time to live value, which is also known as a hop limit.
As the packet passes through a router that TTL is decrement it until when the TTL reaches zero, the
packet is destroyed and an ICMP time exceeded message is returned.
Traceroute works by setting the ttle for a packet to what, sending it towards the requested destination
host and listening for the reply.
When the initiation machine receives a time exceeded response, it examines a packet to determine where
the packet came from.
So this identifies the machine one hop away.
Then the tracing machine generates a new packet with TTYL to.
And uses that response to determine the machine to hops away and so on.
The command traceroute is available on many modern operating systems.
On Unix, like systems such as FreeBSD, Mac OS and Linux, it's available as a command line tool.
On Unix like systems, Traceroute says, by default, a sequence of UDP packets, Traceroute is also
graphically accessible in Mac OS within the network utility suite.
And Microsoft Windows, it's named Traceroute.
And Windows Traceroute sends ICMP a request instead of UDP packets.
For IPV six, the tools sometimes has a name traceroute six or traceroute six.
Let's look at the traceroute command operates in our host machine and virtual machines as well.
So I'm on my host machine, this is Mac OS, and I'll open a terminal screen command space to open the
spotlight search bar and type terminal.
Start the terminal lap and now I'm on a terminal screen.
Traceroute is the command I'll use, so if you run it with no parameter, you got a brief help about
the usage of the command.
So now let's run the command with a target host.
We timed out in the first top.
And in the second one as well, where it happens, no worries and yes, here are the other jobs.
This is the path at the back.
It's follow from my host machine to the target web server.
In Mac OS, you can also trace the packets with a graphical UI, which I mentioned before.
So go to the network utility tool, press command and Space Bar once more to open spotlight and type
network utility and find it and open it.
There's a traceroute tab in the network utility window.
Just type the target host and click the trace button.
Let's see how it all works in Cali.
So now I'm in Cali and I have a terminal screen, open type trace round and hit enter.
So you'll see the help for this particular command and it's a bit more detail than the one in Mac OS.
So now I want to show you the network configuration of my colleague.
Go to college settings, click network adapter, and as you see, we run in that mode where the host
machine Mac provides network address resolution, we'll talk about that soon for all network traffic
and college shares, the IP address of the host.
Now, I want to test the network connection first, so I'll ping the Google DNS 888 Daddy, Daddy and.
Right, that's no problem at all.
You can use control, see keys to end the Pinkman, you know, not just don't use control.
OK, now I'll run the trace route with the target hosting Collie.
The first stop is a gateway prepared by VMware for my virtual machines.
And as you can see, all the other hops are blocked.
We cannot trace packets from the PVM in that mode.
So let's have a look at the traceroute command options once more.
Here there's an option uppercase T, which sends TCP send packets.
Now, I'd like to try the command once more with this option.
OK, so we have the first and the last hop this time.
So now I want to show you the command in a window system.
Here is my up to date Windows eight system.
It has an IP.
Check the connection, Ping, and yes, the network is running good just where we want.
Let's look at the network details first from the network and sharing center.
Click either had zero and then the details button and hear the details.
Default Gateway is nine nine point to DHP is not nine to five four, as you know, these are the devices
prepared by VMware for our net network.
So now I go to the settings of the VMware Fusion in network adapter, we confirm that the VM is in that
network mode.
Now I'm in the command prompt.
As I mentioned, the command is traceroute in Microsoft systems.
So write down the target host and press enter.
So the first stop is, again, the gateway.
And just like in Cali, since this VM is also in that mode, the requests for other hops are timed out.
So while the command is running, I'd like to show you the command help.
So just type traceroute and hit enter.
So we didn't enter the host this time, and here is a usage of the tracer command.
Trece completed, and there is no result given as expected, because we're in that mode.
I know you knew that, but I just wanted to make sure.
So now I'm going to run my Windows VM in bridge mode and try the command once more.
And once again, click the hardware settings icon on the menu bar, VMware Fusion and Select Network
Adapter.
So I'm using Wi-Fi to connect to the Internet right now, so I choose Wi-Fi under the bridge networking
section.
Now, this is the IP address assigned by the DHC peak and the subnet mask of the network, again, is
set by the A.P..
So we'll see how the DHP works.
Just stay with me here.
As you see in the network and sharing center window, the active network disappeared as soon as I changed
the network adapter of the VM.
And a second, the new network is activated, click Ethernet zero and look at that, the details button.
So click on that to see the network settings and those are the new ones.
So now we're in the one nine two to one six eight dot one two x IP block.
And we have a different DHP and gateway run by the network admins of my office building.
So let's go back to the command prompt and trace the route of the package once more.
So first I want to check the network as I always do, so I'll ping the Google DNS.
And yes, we have the Internet connection.
I mean, now is it time to trace the route?
The first request is timed out, remember the results of my host machine, right?
The second request timed out as well.
And here are the other hops, we now have the results.