Our third term in computer science has been focused on networks. After studying a lot of theory about them (uses, types, settings,…), we are now able to do our first practice. It consists in finding our IP settings through two different operating systems: Windows 8 and G-Parted (a type of Linux distribution), in order to compare and contrast the information we have been given. Likewise, we have learned some commands so as to get this information, since it is a very easy way to do it.
⇒ In case you have any problem with a command use, in Linux, -h behind the command or man before it to get help. In Windows you have to write /? if you want help.
1. GETTING OUR BASIC IP SETTINGS:
a) Windows 8:
We have to go to Control Panel, then click on Networks and Internet, enter in Networks and Shared Resources and finally click on Ethernet (it can also be named Local Area Network depending on the computer). [Start menu -> Control Panel -> Networks and Internet -> Networks and Shared Resources -> Ethernet]. This will open a new window with all the information about our computer:
- MAC address (physical address): 70-54-D2-7E-87-50
- IP address (version 4): 192.168.10.45
- Subnet mask: 255.255.255.0 (This means that our IP has 3 of the 4 bytes assigned to the network part, and 1 byte to the host)
- Gateway: 192.168.10.254
- DHCP (Dynamic Host Configuration Protocol): It is enabled, which means that every time we switch on our computer, the byte of the IP assigned to our host changes.
- DNS server: we have got three different DNS servers in IP address and 1 in URL. The ones with IP are 192.168.10.250 (our highschool’s one), and 18.104.22.168 and 22.214.171.124 (the two Google DNS). The one in URL is from our highschool: lopezdemendoza.local.
There is another way of doing this and it is using commands. In Windows, to discover all the IP settings of the computer, we have to use the command ipconfig /all The information given by the command is the same than the previous one but this one is more complete. We can see our host name: info2013.
In Parted Magic we can only look for this information through commands, this time is “ifconfig”. Later we’ll see different types of comands for linux and for windows.
Our IP address now is 192.168.10.57 because we had to do it another day and, since the DHCP is dynamic, the IP has changed. However, the subnet mask and the loopback are the same. Linux is less complete than Windows in this case, but it is useful to compare and contrast the information.
2. GETTING BASIC IP SETTINGS OF ALL THE LAN HOSTS:
a) Windows 8:
For the next steps, both in Windows and Linux we are going to use commands. Now, for this step in Windows, the command we have to use is arp -a. This command will show us the ARP protocol, which is the one in charge of assigning an IP address to every computer. That is the reason why we have a list of computers with their MAC address (physical address) and their IP address at that moment.
In Linux the command is the same: arp -a, and this is what it shows. Many less computers are shown, only 2. One of them is controlador.lopezdemendoza.local.
If we had to look for IP addresses, we will have to do it in windows, because a lot of information is missed with Linux.
3. MAKING A POLL TO LOOPBACK:
A pool is a try to know if our network sends and receives packages correctly. The first one we are going to do is to our loopback, our own computer.
a) Windows 8:
The proper command to do this in Windows is ping <host address>. (< and > are not included, it is just to warn you to write what is between them, in this case loopback address: 127.0.0.1). However, this command only sends 4 packages, and we want to send the double, 8. What we have to do is to add -n 8 at the end, so we are changing the default answer of the command. This are our results:
As we can see 8 packages of 32 bytes each have been sent and receives, none of them got lost. It is so fast that it shows that the speed was 0ms.
In Linux the command is almost the same, the only thing we have to change is -n 8 by -c 8. The packages are a bit heavier, 64 bytes, and the time is more specified, only some tenths of miliseconds. The complete process only takes 7 seconds in total. None of the packages are lost here either.
4. MAKING A POLL TO ONE OF OUR LAN HOSTS:
In order to do complete this step we have taken one IP address from step 2 and used the same command as in step 3 but including this new IP address. Of course we dont have to say that this IP address comes from our LAN Network.
a) Windows 8:
We have had some problems during this process, maybe due to the firewall or the IP configuration of our network. It showed that some or all the packages were lost. To solve this problem, we entered a Windows remote control through another computer.
Problems we had:
In the first photo, two packages were lost. However in the second one, none of them were lost but host destination was also inaccesible.
Here, as you can see, we also changed the IP address in case the previous one had any problem. In this example all the packages were send and received. The maximum time they spent was 1ms.
For this step we have taken one of the hosts IP that we were given in step 2 by Linux. It is 192.168.10.250, but we decided to try to do it with its DNS name: controlador.lopezdemendoza.local. The time is more specified, only some tenths of miliseconds. The complete process only takes a bit more than 7 seconds. None of the packages are lost here either.
5. MAKING A POLL TO AN EXTERNAL HOST
a) Windows 8:
We had the same problem as in the previous step, the firewall or the IP configuration do not allow us to do the poll. We tried with Google’s DNS server. Consequently we lost all the packages.
In Linux, we first tried to do it with our blog URL: skyfallersblog.wordpress.com, but the same problem appeared. Then, we tried again with Google, but we were not lucky either, all packages were lost.
6. TRACING THE ROUTE OF THE PACKAGES:
In this step we are asked to describe the route the packages follow when we connect to our highschool’s virtual class: lopezdemendoza.info
a) Windows 8:
Windows command we have to use for this task is tracert <host address>, in this case tracert lopezdemendoza.info.
When we write the command, this is the information we get. There are sixteen hops the IP has to make in order to reach the address, jumping from host to host and from network to network. It is a very fast process, only lasting some miliseconds each step and 3 seconds in total.
The command to trace routes i Linux is traceroute lopezdemendoza.info. We can see the information given by Linux is almost the same. However, here there is one step less than in Windows and te time does not vary a lot, it is still three seconds in total.
Doing this task we have been able to understand better what a network is, as well as knowing how important they are for the correct work of the computer.
When creating this post, we have been able to figure out what a network really is, and how it really works, as well as its principal settings. Thanks to steps 3, 4 and 5, we now understand that not all the information that we send is received.
To sum up, we found this task at first quite difficult, but thanks to the theory learned before, we finally understood everything we were doing. Likewise, doing the task has also helped us to understand all the theory better, a kind of a mutual process