Networking Basics Flashcards
What is a server and what are it’s uses?
Server is a computer that serves a role of providing services to other devices over a network. For example there could be web hosting servers, database servers, email servers.
What is IP and how it’s built?
IP stands for internet protocol, and it is a numerical adress, that is used to identify devices over a network. It is build by 4 numbers each seperated by a period (which are called octets)
What is DNS,
DNS (Domain Name System) - a system that “changes” domain names into ip adresses, so that way we can connect to websites (server) with using their domain names, instead of ip adresses.
What is a purpose of a hub, a switch, and a router?
Hub is a device that allows differents computers to be connected, creating a network. Switch role is similiar with a difference, that when computer wants to connect to other computer over a network via hub, hub will send the data to every other computer in that network. Switch would send the data only to destined computer in that same situation.
Router is used to connect different networks with each other.
What is a modem?
Modem is a device that demodulates analogue signal that the internet uses, and passes it down to router as a digital signal, that computer use. And vice versa.
What is a difference between modem and a router?
Modem connects your computer to the Internet. A router connects computers together so they can share a modem.
What is a CPU cache?
CPU cache is CPU’s built-in memory. It stores RAM’s frequently used data, so that the CPU can access it without going to RAM, as connecting with RAM is much more slower than accessing CACHE. The process unfolds like this:
If cpu needs some data it will first search it in cache level 1, then level 2, then level 3, and if it doesn’t find it it will search for that data in RAM.
What is TCP?
It stands for Transmission Control Protocol, and it allows computers to connect to each other via network. It makes sure that data transferred is being recieved correctly, or if it is recieved at all.
What is UDP
User Datagram Protocol - it is a transmission protocol that allows computer to send data via network. It doesn’t check if data is being recieved correctly or recieved at all.
What is the use of a PING command?
The ping command is one of the most used tools for troubleshooting, testing, and diagnosing network connectivity issues. Ping works by sending one or more ICMP (Internet Control Message Protocol) Echo Request packages to a specified destination IP on the network and waits for a reply.
Examples:
ping google.com; ping 8.8.8.8 - if there is a problem connecting to google.com, but not to it’s ip (8.8.8.8) then it means there is a problem with DNS.
ping 127.0.0.1 (or localhost) - checks your system networking device.
What is a firewall, and two types of it?
A firewall is a network security device that monitors incoming and outgoing network traffic and permits or blocks data packets based on a set of security rules.
It can either be host-based firewall, or network-based firewall. First one is a piece of software, and it monitors network traffic to the single device. Latter checks traffic to whole network.
What is VLAN?
VLANs are used to divide a physical LAN into multiple broadcast domains to isolate services with the aim of improving the security and management of the network. Hosts within a VLAN can directly communicate only with other hosts in the same VLAN and must use a router to communicate with hosts in other VLANs.
What is FTP?
FTP stands for File Transfer Protocol and, as the name implies, it is a way of transferring files between computers.
What is Telnet and SSH?
Telnet is a system that allows to get access to command line access to a system over a network. SSH (Secure Shell) is the same, but much more secure.
What is port forwarding?
Port forwarding, sometimes called port mapping, allows computers or services in private networks to connect over the internet with other public or private computers or services.
