DNS, IP Address, Web Hosting and the Cloud Flashcards
What does ‘ISP’ mean?
Internet Service Provider
What is an ISP?
A company that provides access to the internet for business and individuals
Give 3 examples of a ISP?
BT Infinity
Sky
Virgin Media
What does URL stand for?
Uniform Resource Locator
What is a URL?
Is the unique web address for every webpage on the internet
Give 3 examples of a URL
www. youtube.com
www. amazon.com
www. bbc.co.uk
What does IP stand for?
Internet Protocol
What is an IP?
A set of rules that govern the activity for the internet and the WWW
What is an IP address?
It is a unique address given to every single device connected to the internet
Give an example of what an IP address would look like
76.215.67.190
What is the difference between a static IP address and a dynamic IP address
A static IP address are permanent and never change, whereas the dynamic IP address are temporary and are assigned to the device every time it accesses the internet
What are the 2 types of IP address?
Static
Dynamic
Where are websites hosted?
On a server
What does DNS stand for?
Domain Name System
What job does the DNS do?
It translates a web address into the correct IP address for the server or service that you have requested
What is a DNS server?
A database of IP addresses and they are constantly updated by other DNS servers
What are the 2 advantages of DNS?
You do not need to remember any IP addresses of websites
So long as you are connected to a DNS server you can access any website for which there is a stored IP address
How does a DNS work?
You type in the name of the website or web page that you wish to visit
Your browser makes contact with a DNS server. The server contains a database that matches the domain name up with its registered IP address
The DNS sends this information back to your computer
Your computer attaches the IP address to the data packet to be sent
The data packet travels over the internet to its destination
The server where the website is stored sends back the data which you requested
What happens if the DNS can’t find the address?
It searches other DNS servers
What is a web site made up of?
One or more web pages along with any images or other media such as video embedded within each web page
What is a web site?
A set of files and folders
What is needed for a web site to work correctly?
It needs to be ‘hosted’ on a web server
What is local hosting?
When you host a web site on your home PC. To do this you would need to set up your PC as a web server and allow others to connect to it and access the web files that you store
What is the main advantage with hosting locally?
It’s cheaper than external hosting
What are 6 issues with local hosting?
Bandwidth Computer needs to be always on Need technical knowledge Firewall Payments Dynamic IP
What is external hosting?
Is where you pay a web hosting company to host your website on one of their servers
What do big companies do for external hosting your website?
Provide hard disk space on their server to host your site
Ensure that your site remains running and available at all times
Provide the bandwidth required to allow users to access your site
Provide maintenance of the server
Regular backups of your site and if necessary provide a rollback
Provide security to protect your sites from malicious attack
Provide technical help
What are the 3 types of external hosting?
Shared web hosting
Dedicated server
Virtual server
What is shared web hosting?
Where many sites are hosted on the same web server
What are 2 disadvantages with shared web hosting?
All users share resources such as RAM, Bandwidth, CPU time
Have to accept advertising on your site
What is dedicated server?
Where the website is hosted on its own server
When are dedicated servers used?
Often used by companies who have a lot of website traffic
What is a disadvantage with dedicated servers?
It is an expensive option as you cannot share the costs of renting the server with other users
What is a virtual server?
A powerful server that runs specialist software allowing it to create many ‘virtual servers’ within itself. These are then rented out to customers to host their web site
What is an advantage of virtual server hosting?
Everyone shares the cost of it and so prices are kept low
What is the cloud?
A range of software and services that run on the internet rather than on your PC
Give some examples of cloud services
Online hosting of web page data
Online file and media storage (Dropbox)
Streaming services of films and other media (Netflix)
Email services
What are some advantages of cloud services?
You can access your data from any device with an internet connection
Documents and files can be worked on simultaneously by different people e.g. GoogleDocs
You can store large files online and reduce the amount of storage space needed on your home device.
You can access the latest versions of software - it won’t ever become outdated
Online applications e.g. Office 365
Your work is automatically backed up, you don’t have to remember to save it
What are some disadvantages of cloud services?
If you don’t have an internet connection you can’t access any of the services
If you forget your login details you can’t access the services
Most of the services incur a cost, either a one-off payment or an ongoing monthly fee
Your files and personal data might not be stored in the UK and so won’t be subject to the UK data laws
There is a risk of online hackers being able to access your private data and files
