RGB:2563<\/span>=16 million colors. Quality is 8,16,32 bit<\/h6>\r\nFirewall<\/h4>\r\n
prevent unwanted trafic into the network.it contains access control list that contains ip,permission,protocol,destination,port fields.<\/p>\r\n
\r\n\r\n\r\nip address<\/th>\r\n permission<\/th>\r\n protocol<\/th>\r\n destination<\/th>\r\n port<\/th>\r\n<\/tr>\r\n \r\n192.168.1.11<\/td>\r\n allow<\/td>\r\n tcp<\/td>\r\n any<\/td>\r\n 80<\/td>\r\n<\/tr>\r\n \r\n192.168.1.12<\/td>\r\n allow<\/td>\r\n udp<\/td>\r\n 10.1.1.1<\/td>\r\n 23<\/td>\r\n<\/tr>\r\n \r\nany<\/td>\r\n deny<\/td>\r\n tcp<\/td>\r\n any<\/td>\r\n 80<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\nfirelwall rule can be port no,ip address,keywords,domain name,protocol.in above rules only port 80,23 are allow.<\/span><\/p>\r\nTypes<\/h2>\r\n\r\n- Host based firewall<\/li>\r\n<\/ol>\r\n
\r\n- A software on host machine ,work as firewall<\/li>\r\n
- Network based firewall<\/li>\r\n<\/ul>\r\n
\r\n- combination of hardware and software that protects whole network ie some router have built in firewall<\/li>\r\n<\/ul>\r\n
<\/p>\r\n
Wireless security<\/h4>\r\n\r\n\r\n- WEP (Wired Equivalent privacy): <\/span>developed in 1999,40bit encryption key,easy to hack.<\/li>\r\n
- WPA (WI-FI protected Access): <\/span>strong encryption,use TKIP(temporal key integrity protocol) that changes keys.<\/li>\r\n
- WPA 2<\/span> strong security,use AES (Advance encryption standard).Only brute force work.<\/li>\r\n
- WPA 3 <\/span>next generation,introduced in 2018.<\/li>\r\n<\/ul>\r\n<\/ul>\r\n
WPS (WIFI Protected Setup) method<\/span> join secure wireless network with easy methods ie push button or PIN.<\/p>\r\nAccess control or mac filitring method<\/span> MAC address, used to connect with wifi.<\/p>\r\nMesh WI-FI<\/h2>\r\n\r\n- If a router has week signals, we use wifi extender (hardware) that have his own ssid & password.\r\n
\r\n- WIFI Extender: <\/span>extends the range of wifi signals.<\/li>\r\n
- it cant amplify signals,but it get access from near router and broadcast its signals.<\/li>\r\n
- ie ssid:PTCL<\/span> is main router and ssid:PTCLext1<\/span> is extender<\/li>\r\n<\/ul>\r\n<\/li>\r\n
- Mesh wifi: <\/span>A group of routers or wifi points,that are placed in different locations inside a place.They are connected with each other wirelessly.<\/li>\r\n
- A signle SSID (network name) is used for all wifi points<\/li>\r\n<\/ul>\r\n
DMZ (Demilitarized zone) used to improve the security of network.<\/h2>\r\n\r\n- The data before (ie web server) firewall is called DMZ Zone.<\/span><\/li>\r\n
- Goto roter config and setup DMZ settings.<\/li>\r\n<\/ul>\r\n
BIOS, CMOS, UFFI<\/h2>\r\n\r\n- BIOS (basic input output system)<\/li>\r\n
\r\n- Bios is firmware that built on motherbord that initializes the computer hardware as computer is being booted<\/li>\r\n
- then searched for boot devices.<\/li>\r\n
- BIOS run POST (power on self test ) when computer is turn on first time<\/li>\r\n
- if POST is passed Operating system is loaded<\/li>\r\n
- it is non volatile.<\/li>\r\n<\/ul>\r\n
- CMOS<\/li>\r\n
\r\n- DATE & time, hardware settings,boot sequence setting in BIOS is stored in CMOS. ie cell on motherbord<\/li>\r\n
- its volatile & when bettry is removed BIOS configration return to default settings<\/li>\r\n<\/ul>\r\n
- UEFI (unified extensible firmware interface)<\/li>\r\n
\r\n- New version of BIOS, ie it has GUI<\/li>\r\n<\/ul>\r\n<\/ul>\r\n
NAS (network attached storage) vs SAN (storage area network)<\/h2>\r\n\r\n- NAS: <\/span>a centralized storage device for storing data on network.its single point of faileur.ie collection of 10 HDD<\/li>\r\n
- SAN: <\/span>a high speed dedicated network that store and provide access to large amount of data.its use servers,switches & HDD's & use FIBER optic <\/span>,& very expensive<\/li>\r\n<\/ul>\r\n
ARP (address resolution protocol)<\/h2>\r\n\r\n- protocol used to resolve ip addresses to mac addresses.<\/li>\r\n
- MAC ADDRESS is needed for communication on LAN<\/li>\r\n
- check in cmd \"arp -a\" to check arp cache<\/li>\r\n
- Computer a broadcast (who is 1.1.1.1 i need MAC) & 1.1.1.1 replies his MAC & communication take place.<\/li>\r\n
- Now arp entries also stored in arp cache for next time communication<\/li>\r\n
- Types of arp entries<\/span>Dynamic entries (auto), static entries (arp -s 192.168.1.1 ff-gsd-33-dsf)<\/li>\r\n<\/ul>\r\n
NAT (network address translation)<\/h2>\r\n\r\n- translate ip addresses to another ip addresses due to limited amount of public ipv4 address<\/li>\r\n
- 4294967296 ip's are not enough<\/li>\r\n
- so engineers introduced NAT & private ip addresses<\/li>\r\n
- types of ipv4 <\/span>are public & private<\/li>\r\n
- Public ip address: <\/span>publically registered on internet.we must have an public ip for communication<\/li>\r\n
- Private ip address:<\/span> no publically registed, we cant access internet with it,only used in home or business (internally).<\/li>\r\n
- we need to buy public IP by internet service providers to access internet that is expansive,wastage of IPs,un necessary<\/li>\r\n
- if every device get public ipv4 address, than we ran out of IPv4<\/li>\r\n
- So get public ip for main device (ir router) , and router will assign private IP's (using NAT) to our other devices<\/li>\r\n
- In future we use ipv6 () instead of NAT and private IP addresses.<\/li>\r\n<\/ul>\r\n
VLAN (virtual area Network)<\/h2>\r\n\r\n- VLAN's can logically create several virtual networks to separate the network broadcast trafic.<\/li>\r\n
- we make broadcast domain ie VLAN 10, VLAN 20.<\/li>\r\n<\/ul>\r\n
VTP (Vlan Tranking Protocol)<\/h2>\r\n\r\n- use to configure a switch<\/li>\r\n<\/ul>\r\n
SMTP (simple mail transfer protocol)<\/h2>\r\n\r\n- SMTP is protocol for sending emails.<\/li>\r\n
- our message sended to smtp server,ie for gmail smtp.gmail.com is smtp server address<\/li>\r\n
- Smtp server send email to Receipient email server<\/li>\r\n
- Recipient download email using POP or IMAP protocols or use smtp server using web<\/li>\r\n
- SMTP use TCP protocol<\/li>\r\n<\/ul>\r\n
POP3 vs IMAP<\/h2>\r\n\r\n- use for retrieving emails from email server<\/li>\r\n
- POP3: <\/span>post office protocol, only download emails to inbox. no sent items,no syncronization,<\/li>\r\n
- IMAP: <\/span>internet message access protocol, retrive emails, view emails, syncronizations also.<\/li>\r\n
- incomming mail server : pop.gmail.com || smtp.gmail.com<\/li>\r\n<\/ul>\r\n
Modem<\/h2>\r\n\r\n- bring internet in home, use to demodulates (incoming analog to digital) and Modulates (outgoing digital to analog).<\/li>\r\n<\/ul>\r\n
Routers<\/h2>\r\n\r\n- Router passes internet connection to all of your devices.<\/li>\r\n
- if <=4 devices no need of router, we will use four ports of modem<\/li>\r\n<\/ul>\r\n
Printers<\/h2>\r\n\r\n- Inkject: <\/span>most comman,use ink, use tinny dots.<\/li>\r\n
- Laser: <\/span>high quality print,expensive,use toner,<\/li>\r\n
- Dot matrix: <\/span>old technology, noisemlow quality.use ink.<\/li>\r\n<\/ul>\r\n
Defragmentation<\/h2>\r\n\r\n- reduces the amount of fragmented files on hard drive<\/li>\r\n
- save related data on same physical locations<\/li>\r\n
- related files scatered on different locations is called Fragmentation<\/span><\/li>\r\n
- you only have to do a defrag on mechanical hard drives.<\/li>\r\n<\/ul>\r\n
hub,switch,router<\/h2>\r\n\r\n- HUB: all devices receive a data packets,<\/li>\r\n
- Switch: intellegent, send data packet only to destination port using switch<\/li>\r\n
- hub and switch are used for LAN,not used to exchange data outside their own networks<\/li>\r\n
- Router: routes data from one network to another based on ip address.Router reject packets of another networks.<\/li>\r\n
- Hub & switch used to create network and router connect networks<\/li>\r\n<\/ul>\r\n
CPU CACHE<\/h2>\r\n\r\n- store copy of data from RAM, that used again & again<\/li>\r\n
- L1 CACHE: very fast same as cpu,part of cpu,small size<\/li>\r\n
- L2 CACHE: large than L1,slow than l1,cpu first read l1,than l2<\/li>\r\n
- L3 CACHE: large than l2,slow than l2,cpu read it if data is not readed in l2<\/li>\r\n<\/ul>\r\n
TCP (transmission control protocol)<\/h2>\r\n\r\n- communication between two computers need to be reliable,successfully delivery,<\/li>\r\n
- it is connection oriented protocol: need a connection before communication with following three steps\r\n
\r\n- sender send a message SYN<\/li>\r\n
- reciever send SYN ACK to sender<\/li>\r\n
- send again send ACK RECEIVED to reciver<\/li>\r\n<\/ol>\r\n<\/li>\r\n
- <\/li>\r\n<\/ul>\r\n
UDP (user datagram protocol)<\/h2>\r\n\r\n- Same as TCP but connection less.<\/li>\r\n
- faster than TCP But not reliabe,no guarntee of sending data<\/li>\r\n<\/ul>\r\n
Port forwarding<\/h2>\r\n\r\n- Connect to specific computer or service within a private network<\/li>\r\n
- remote desktop connection in microsoft windows<\/li>\r\n
- router send your requesr if port is finded<\/li>\r\n
- port 80 for web pages, 20,21 for ftp,443 for https<\/li>\r\n<\/ul>\r\n
IP ADDRESS<\/h2>\r\n\r\n- identifier for a device on a network<\/li>\r\n
- ipv4 is 32 bits having for octects.<\/li>\r\n
![\"\"](\"https:\/\/i.postimg.cc\/vT1Cd0wC\/MIT-01-ip.png\")
<\/li>\r\n- ipv6 is next genration of IP address having 128 bits hexadecimals<\/li>\r\n
- ipv6 have 8 sets of 16 bits<\/li>\r\n
- each hexadecimal charter represent 4 bits<\/li>\r\n
![\"\"](\"https:\/\/i.postimg.cc\/Bnx967P0\/MIT-02-ip.png\")
<\/li>\r\n<\/ul>\r\nchipset<\/h2>\r\n\r\n- collection of chips in a single case<\/li>\r\n
- chipset contain many transisters,registers.<\/li>\r\n<\/ul>","category_id":"25","is_private":"0","created_at":"2023-08-16T16:15:54.000000Z","updated_at":"2023-08-16T16:15:54.000000Z","category":{"id":25,"user_id":"1","name":"Mater In computers","slug":"mater-in-computers-4twm","parent_id":null,"created_at":"2023-08-16T16:14:38.000000Z","updated_at":"2023-08-16T16:14:38.000000Z"},"user":{"id":1,"name":"R GONDAL","email":"rizikmw@gmail.com","email_verified_at":null,"two_factor_confirmed_at":null,"current_team_id":"1","profile_photo_path":null,"created_at":"2023-03-12T10:49:33.000000Z","updated_at":"2025-01-10T12:59:00.000000Z","profile_photo_url":"https:\/\/ui-avatars.com\/api\/?name=R+G&color=7F9CF5&background=EBF4FF"}},"pageDesc":"Graphics Grayscale image use 0-255 values, 28, 0 used for black and 255 used for white RGB:2563=16 million colors. Quality is 8,16,32 bit Fi - computer science basic TERMS (Updated: August 16, 2023) - Read more about computer science basic TERMS at my programming site [SITE]","categories":[]}
firelwall rule can be port no,ip address,keywords,domain name,protocol.in above rules only port 80,23 are allow.<\/span><\/p>\r\n <\/p>\r\n WPS (WIFI Protected Setup) method<\/span> join secure wireless network with easy methods ie push button or PIN.<\/p>\r\n Access control or mac filitring method<\/span> MAC address, used to connect with wifi.<\/p>\r\nTypes<\/h2>\r\n
\r\n
\r\n
\r\n
Wireless security<\/h4>\r\n
\r\n
\r\n
Mesh WI-FI<\/h2>\r\n
\r\n
\r\n
DMZ (Demilitarized zone) used to improve the security of network.<\/h2>\r\n
\r\n
BIOS, CMOS, UFFI<\/h2>\r\n
\r\n
\r\n
\r\n
\r\n
NAS (network attached storage) vs SAN (storage area network)<\/h2>\r\n
\r\n
ARP (address resolution protocol)<\/h2>\r\n
\r\n
NAT (network address translation)<\/h2>\r\n
\r\n
VLAN (virtual area Network)<\/h2>\r\n
\r\n
VTP (Vlan Tranking Protocol)<\/h2>\r\n
\r\n
SMTP (simple mail transfer protocol)<\/h2>\r\n
\r\n
POP3 vs IMAP<\/h2>\r\n
\r\n
Modem<\/h2>\r\n
\r\n
Routers<\/h2>\r\n
\r\n
Printers<\/h2>\r\n
\r\n
Defragmentation<\/h2>\r\n
\r\n
hub,switch,router<\/h2>\r\n
\r\n
CPU CACHE<\/h2>\r\n
\r\n
TCP (transmission control protocol)<\/h2>\r\n
\r\n
\r\n
UDP (user datagram protocol)<\/h2>\r\n
\r\n
Port forwarding<\/h2>\r\n
\r\n
IP ADDRESS<\/h2>\r\n
\r\n
<\/li>\r\n<\/li>\r\n<\/ul>\r\nchipset<\/h2>\r\n
\r\n