What happened to the lab today?

     My responsibility in the computer lab was to make sure that "computer "1 had access to certain applications throughout all the users. For example: Microsoft word needed to be "read and write" for Student 1, Student 2, and Student 3. One of the main things that i needed to do was make sure that all users were able to access parallels, in order to easily switch between 2 operating systems.

     First off, before I am able to change anything, I needed adminstrator access to the computer, which I did not at the time. To solve this problem, I had done a simple hack to the computer. I went into single user mode, then I deleted ".AppleSetupDone" using this command:

rm -rf /var/db/.AppleSetupDone

    Have you ever gotten a new Mac computer before? If you have then you should be familiar with the very first setup screen when you first turned on your computer. Once you have completed the setup, a file called ".AppleSetupDone" then instals on your computer to let the computer know, not to go to the setup screen anymore, but instead, bring you straight to the login process.
    
     What I did, was delete this in order to go through the setup in order to gain my adminstrator access into the computer in order for me to make any changes. Once I set up my new administrator account, then I got straight to work.

     I took the folders and applications of the programs that Ms. Ramirez had wanted me to make accessable to all the users, and one by one I changed the permission settings for each of them. It was time consuming, as I had to retype my password a thousand times, and I did not know any shortcut or command to temporarily disable the chain password.

     Once I was done with that, I needed to put the parallels setup into the shared folder, for all the users of the computer to access it. Lastly, I checked two student accounts in order to make sure that my changes worked. "student 2" and "student 3".

     I had discovered that my changes were successful, and that every user was able to access the parallels setup.

How Does UDP Work?

UDP

UDP also known as User Datagram Protocol,  is a simple protocol using basic functionality. With UDP, computer applications can send messages to other hosts on an IP network without requiring prior communications to set up transmission channels or data paths.

Transport Layer Problems

Blackberry
     On October 10, 2011, Blackberry had an outage in Europe, Middle East, and Africa. By October 12, Blackberry internet service went down in North America. Blackberry apparently had an unfortunate issue regarding data overload due to switch failures in their two data centers which was the main problem that had caused their service disruptions.

Playstation Network (PSN)

     On april, PSN got hacked by "anonymous", who was known to be part of the 4chan website. Members of 4chan were also responsible for hacking other popular websites and sending DDoS attacks to their servers. The attack on PSN occured between April 17, 2011 and April 19, 2011. During the hacking, 77 million accounts were stolen, making it one of the largest data security breaches in history. Itprevented Playstation 3 and Playstation Portable users from playing online. This forced sony to turn off the PSN on April 20, 2011.
     During the Attack, they discovered that the intruders planted a file on one of their Sony Online Entertainment servers named "Anonymous" with the words "We are Legion". Playstation is now using inhanced levels of data protection and encryption; enhanced abilities to detect software intrusions, unauthorized access and unusual activity patterns; additional firewalls, etc.
     Sony had not released any information as of how they got hacked, or what they did to stop the intruders, as that even is now an ongoing criminal investigation. The inormation could be used to exploit vunerbilities in systems other thanSony's that have similar architecture to the PSN.

How DHCP works

Dynamic host configuration protocol is also known as DHCP. DHCP, is a protocol for hosts on internet protocol (IP) networks. This provides dynamic IP assignment. It means that a host can assign an IP address from a subnet or "pool"

Advantages of P2P and Client/Server

Which Network-type is more centralized?

Peer to peer networks (P2P) are more centralized than Client server networks. In P2P, Clients are able to interact with each P2P network participants without the need of servers or stable hosts. Therefore, if one computer is not responding, then it will only affect that one individual without disrupting other network participants.

However, In a Server/Client network, if a server or host crashes, or is responding slowly due to bandwidth or any other issue, it will affect all the clients that are trying to recieve data from that particular server.

-------------------------------------------------------------------------------------------

Advantages of Client/Server Network

Although Client/Server networks are not as centralized as P2P networks, there are termendous advantages to this type of network. Anyone who is running a server with information on it, and runs that information through HTTP and publishes it on the internet, then absolutely anyone who has access to the internet also have access to the information stored on the server, making it very easy for people to research.

For example: Google.com

Google.com one of the most popular search engines today. Their servers have information to the most visited websites based on how many people have searched it, or how people actually go on that website. Whichever website has the most, then that link would be first on the list when you look things up.

-P2P networking does not have this capability to share with others accross countries. Only the participants of the network is able to share data with each other, and no one else.