Internet

Name: Mathijs
Student number: 12345678

Questions

  1. The internet is a large network of computers that each have an address called an IP address and the computers communicate using protocols.
  2. When the browser communicates with a web server it follows rules of communication called protocols. Hyper Text Transfer Protocol (HTTP) and Hyper Text Transfer Protocol Secure (HTTPS) are protocols that transmit hypertext between a client and a server. The plaintext transmitted by HTTP is not encrypted, so the plaintext can be intercepted, and the sensitive data can be read. In contrast, HTTPS uses end to end encryption through a system called Secure Sockets Layer (SSL), which protects the plaintext.
  3. The private IP address of a device is used to communicate with other devices on the same local network. An advantage of a private IP address is that it can only be traced by another device on the same local network. A disadvantage of a private IP address is that it cannot be used to access the internet for this a public IP address is needed.
  4. The packets are transmitted from your computer/client through a path of routers, and then they arrive at the server. However, the packets do not always us the same route, since the fastest route may change due to traffic.
  5. An access point allows wireless devices such as a smartphone, smart tv, and printer to connect to a wired network over WIFI. A firewall is a security feature that blocks malicious packets entering the local network from the internet and controls outgoing packets exiting the local network.
  6. First, the device needs an IP address to connect to the network. Thus, the computer/client will request an IP address from the DHCP-server, which will allocate an IP address to the device. The computer/client transmits a package to the domain name system (DNS) server for the corresponding IP address to the https://www.harvard.edu domain. Then, the client transmits a packet to the Harvard web server with a TCP-port to specify the protocol. The TCP-port 443 is used this indicates that the HTTPS protocol should be used. Next, the web server receives the packet and can interpret the instructions because it understands the HTTPS protocol. Then the webserver will transmit the webpage to the client using packets. The packets contain part of the webpage, a return IP address, and destination IP address. The packets follow the fastest available path of routers and will finally be received by the home router. Since the home router keeps track of which device, and its private IP address made the request, it follows that the router can transmit the data to the correct device.
  7. The internet service provider (ISP) that offer internet service in my neighbourhood is ZIGGO. The ISP provides 125 Megabytes per second download speed and 12.5 megabytes per second of upload speed. Thus, the upload and download speed are asymmetric. This cost of this service is 27.50 euros per month.
  8. One topic that caught my attention from the lecture is the distinction between public and private IP addresses as I was not aware that there was a difference. Each device on a local network has a private IP address requested to the DHCP-server on the router. Devices on this local network can communicate with each other using their private IP addresses. However, the private IP address cannot be used to connect to the internet. In contrast a public IP address is used on a public network such as the internet, and the internet provider usually provides only 1 public IP address per customer. Therefore, the devices on the local network need to share one public IP address, this also hides the private addresses from the public. This can be achieved using Network Adress Translation (NAT). When a device on the local network sends a request to the NAT device, which could be the router, the router will replace the private IP address with the public IP address and assigns a unique port number. When the router receives the response packet, it will transmit those packets to the device on the local network with the correct private IP address and port number.

References

←Back to blog