Electronic+security

= Logical Security =

 Logical security (or access security) is about preventing unauthorised access to the network or to individual accounts.

 It involves managing logins and passwords, which is a feature of the network operating system.

 Logical security also involves using a firewall to stop any unwanted intrusion from hackers.

= Data Security =

 Data security involves protecting the data from loss or accidental damage. Hard drives store data on magnetic discs, which are very reliable and rarely fail. A hard drive should last many years but you may not get a warning when it fails.

 The data on hard drives can be corrupted by large magnetic fields, e.g. those found in speakers or transformers.

 Fires, floods, natural disasters and terrorist incidents are rare but do happen. Organisations cannot take the risk of losing their data.

 A network could be disabled by a virus or other malware.

 Some files can be protected with an additional password which is needed to edit them.

 Some files can be stored on the network as read- only, which means that none of the users can edit them.

 Work stored on a school network is usually backed up each evening by the network manager. Businesses back up after each day’s trading.

= **Firewalls** = firewall is a hard ware or software that determines which data is allowed to enter and leave a network. hardware can be built into network routers or can dedicated to computers. software firewalls are computer programs that can be installed and do the same job as a hardware firewalls if software firewalls is on a desktop computer it sometime referred as a personal firewall

firewalls help to secure a computer by preventing network access from external unauthorized users and it also controls what programs and users are allowed to connect to a external network such as internet. firewalls are used to control to allow or block traffic using these methods


 * i.p. addresses : addresses of specific computers allowed or denied access
 * Domain names: access to specific websites such as social networks can be blocked by specifying name
 * protocols and ports:different protocols such as http,smtp,pop3,ftp can be blocked or allowed as needed . protocols usually use a standard port. both protocols and ports can be blocked

= **Proxy Servers** = proxy servers act as a middle step between two computers, which are usually between a computer on lan and a web server on the internet. communication between both are passed through the proxy server allowing it to preform tasks such as catching, filtering and logging data. because of these tasks performed proxy servers are a common way in which to implement firewalls functionality and a record of users web activity. catching is a process used to speed up activities such as web browsing proxy servers keep a copy of commonly requested material example is a web page in a storage place called a cache. when a user types in the requested web page, proxy server will provide it from local cache rather than retrieving from the internet