CIS 454 Assignment 5
1)​ Taken at 1 pm
Taken at 10 AM
The first field is hop number. It maxes out at 30 by default but can be changed with a few extra
flags. The second, third and fourth field is the time it takes for the packet to reach the router, the
destination, and back to the host device. The fifth field is the ip address of the destination after it
reaches it. It also attempts to resolve the host name of the destination by default. I did not
observe any notable difference between times of days.
2)
Ping uses Internet Control Message Protocol (ICMP). It sends an echo request to the other host.
In each example I changed the packet size from 64 to 516 to 1024. The time is the amount of
time it took for the destination to receive the packet. The TTL is the time to live for the packet. If
time were to expire then the packet would be considered dropped by the host.
3)
My personal machine
My home server (Through SSH)
Spirit server (Through SSH)
Iface is the networking connection available on the device. Next is the MTU is the maximum
transmission unit which is the maximum size packet that can be sent through that interface.
RX-OK is the amount of packets received correctly. RX-ERR is the amount of packets received
that were errors. RX-DRP is the amount of packets dropped over a given interface. RX-OVR is
the amount of packets received and dropped because they were overrun or over filled. TX is the
same thing but for transmitted frames.
4)
Nslookup uses a reverse DNS lookup to find the IP address of a site or server. DNS stands for
Domain Name Server. It is what lets you put in a domain name of a site in your browser instead
of the IP address of where you would like to connect.
5) DHCP is a protocol used for automatic addressing of IP addresses. The reason we use this
method is so we don’t have to manually assign IP addresses across the internet. These are
typically done by routers or dedicated servers to manage and maintain. The protocol involves
having a pool of IP addresses and when requested, pulls an address from the pool and assigns it
to a host. This IP address is leased to the host and is only valid for a specified time. Once the
lease expires it is required that the host renews it. The DHCP server can also be in charge of
hosting a DNS server.
The computers in the engineering department have static ip addresses. By using SSH to get into
the spirit server, we can see that the ip addresses follow a pattern of 137.148.204.* where the star
is any given number between 14 and 40. It is likely that these computers were given these ip
addresses in order for easy management and ability to connect to them via SSH. Because of this,
it is likely that they do not have DHCP enabled. I found this out by sshing into the spirit server
and running the ARP command in the terminal.
With this we can see the IP addresses of all the computers that spirit can see via the network.
Looking at the IP addresses gave it away that there was a pattern in the networking addresses.
Turning off DHCP can be done in the networking settings of windows. There you can also set a
static IP address and set up a DNS server to use.