Networking Flashcards
Where is the HTTP protocol used?
Worldwide Web
What is the SMTP protocol used for?
Sending/receiving emails
What is the FTP protocol used for?
File transfers over a network
What is the SMB protocol used for?
Shared folder access over a network
What are port numbers used for?
Since applications do not have direct access to network hardware, the OS will help service the network requests.
The OS assigns each request from an application with a random (source) port number, so that the response can be passed back to the correct application.
What does 127.0.0.1 refer to?
loopback network interface/localhost
What is packet forwarding?
It is the process by which data is sent from computer to computer until it reaches its destination.
What is the name of the packet forwarding model used by the TCP and UDP protocols?
Unicasting, whereby data is forwarded from server to server, until it reaches its destination.
How does unicast packet forwarding work?
Each computer on the network is connected to a gateway.
When an application needs to send data to a destination (IP address), the computer checks all other computers connected to it to see if the destination is listed there.
If not, the data is forwarded to the computer’s gateway.
At the gateway, the process is repeated.
If the destination is not in the list of computers in the gateway, the data is forwarded to the next gateway and checked again until the destination is found and the packet is sent to the destination.
What are the steps involved in DNS lookup?
- DNS client checks its DNS cache for DNS entries containing the domain name. If one is found, the corresponding IP address is used. Otherwise …
- DNS client sends a DNS lookup request to a (recursive) DNS resolver.
- DNS resolver checks its own DNS records for the domain name. If DNS record is found, DNS server returns response with the requested IP address. Otherwise, it sends the request to a DNS root server.
- The root server sends the address of the authoritative (TLD) DNS server request to the resolver.
- The resolver queries the authoritative DNS server for the IP address.
- The resolver sends the IP address back to the client.
What is the DNS cache?
It is a location where the computer stores the IP addresses returned for the domains. This is done so that next time a DNS lookup is requested, the computer checks in the DNS cache first, to minimize requests to the DNS server.
The DNS cache may need to be flushed if it gets outdated.
What do top level domains (TLDs) refer to?
Suffixes such as .gov, .edu and .com.
What is a protocol?
It is a set of rules for communication agreed upon by both the sender and receiver.
What is a protocol suite?
It is a collection of related protocols that are designed to work together.
What is the IP protocol? What is its purpose?
It forms the Internet layer of the TCP/IP model. Its purpose is to identify computers on the Internet. This allows packet routing to be used for the Internet.
