diff --git a/00. Jeremy's IT LAB CCNA course.md b/00. Jeremy's IT LAB CCNA course.md new file mode 100644 index 0000000..c496c0a --- /dev/null +++ b/00. Jeremy's IT LAB CCNA course.md @@ -0,0 +1,17 @@ +--- +id: Jeremy's IT LAB CCNA course +aliases: [] +tags: + - CCNA +--- + +# Jeremy's IT LAB CCNA course + +[link](https://www.youtube.com/watch?v=H8W9oMNSuwo&list=PLxbwE86jKRgMpuZuLBivzlM8s2Dk5lXBQ) +[drive](https://drive.google.com/drive/folders/1PwK_jWqfUtOjV7gHt8ODutq9QA5cxCgi) + +[[Network Devices - CCNA]] +[[Interfaces and Cables - CCNA]] +[[How the TCPIP Model Actually Works]] +[[Intro to the CLI]] +[[Ethernet LAN Switching]] diff --git a/01. Network Devices - CCNA.md b/01. Network Devices - CCNA.md new file mode 100644 index 0000000..8abd94a --- /dev/null +++ b/01. Network Devices - CCNA.md @@ -0,0 +1,132 @@ +--- +id: 1771668476-SUCR +aliases: + - 01. Network Devices - CCNA +tags: + - CCNA +--- + +# Network Devices + +## What is a network + +A computer network is a digital telecommunications network which allows nodes to share resources. + +### [[Router]] + +Is represented with a circle where inside there are 2 horizontal arrow poiting +inside and 2 vertical arrow pointing outside + +Have fewer network interfaces than switches +Are used to provide connectivity **between** LANs +Are therefore used to send data over the Internet + +example of [[Cisco]] routers: +- [[ISR 1000]] +- [[ISR 900]] +- [[ISR 4000]] + +### [[Switch]] + +Is represented with square 4 horizontal 2 poiting to the left and 2 pointing to the right + +Switches a used to connect a [[LAN]] + +Have many network interfaces/oirts for end hosts to connect to (usually 24) +Provide connectivity to hosts within the same LAN +do not provide connectivity between LANs/ over the internet + +example of [[Cisco]] switches: +- [[Catalyst 9200]] +- [[Catalyst 3650]] + +### [[Firewall]] + +Is represented with square with a brickwall inside of it + +Monintor and control network traffic based on configured rules. +Can be placed 'Inside' the network, or 'outside' the network +Are known as 'Next-Generation Firewall' when they include more modern and advanced filtering capabilities + + +example of [[Cisco]] firewalls: +- [[ASA 5500-X]] +- [[Firepower 2100]] + +#### Host-based firewalls + +Are software applications that filter traffic entering and exiting a host machine, like a [[PC]] + + +### [[Server]] + +Is represented with square with a computer inside of it + +**A device that provides functions or services for clients.** + +The same device can be a client in some situations, and a server in other situations. + +### [[Client]] + +Is represented with square with a monitor inside of it + +Can be a computer, a laptop, or a phone + +**A client is a device that accesses a service made available by a server.** + +### [[Internet]] + +Is represented with circle with a cloud inside of it + +## Building a network + +2 pc connected together create a network + +## Quiz + +1. Your company wants to purchase some network hardware to which they can plug the 30 PCs in your department. +which type of network device is appropriate? + +a) A router +b) A firewall +c) A switch +d) A server + +**good answer: c** + +2. You received a video file from your friend's [[Apple]] [[iPhone]] using [[AirDrop]]. +What was his iPhone functioning as in that transaction? + +a) A server +b) A client +c) A LAN + +**good answer: a** + +3. what is your computer or smartphone functioning as while you watch this video? + +a) A server +b) An end host +c) A client + +**good answer: c** + +4. Your company wants to purchase some network hardware to connect its separate network together. +what kind of network device is appropriate ? + +a) A firewall +b) A host +c) a LAN +d) A router + +**good answer: d** + +5. Your company wants to upgrade its old network firewall that has been in use for several years to one that provides more advanced function. +What kind of firewall should they purchase ? + +a) A host-based firewall +b) A next-level firewall +c) A next-generation firewall +d) A top-layer firewall + +**good answer: c** diff --git a/02. Interfaces and Cables - CCNA.md b/02. Interfaces and Cables - CCNA.md new file mode 100644 index 0000000..d642b84 --- /dev/null +++ b/02. Interfaces and Cables - CCNA.md @@ -0,0 +1,184 @@ +--- +id: 1771825730-VZFA +aliases: + - 02. Interfaces and Cables - CCNA +tags: + - CCNA +--- + +# Interfaces and Cables + +Front of a switch example phrase above the interfaces +10/100/1000 Base-T Ports ( 1 -24) - Ports are Auto MDIX + +## [[RJ-45]] + +Registerred Jack + +## Etrhernet + +Etrhernet is a collection of network protocols/standards. + +## Network Protocols +Why do we need network protocols +For Industry standard that everybody follows + +## [[Bits]] and [[Bytes]] + +it a value represented by 0 and 1 +a bytes is a series of 8 bits + +Speed is measured in bits per second (kbps, Mbps, Gbps, etc) not bytes per seconds. + +However for [[Hard drives]] we count the bytes + +1 kilobit (kb) - 1,000 bits +1 megabit (Mb) - 1,000,000 bits +1 gigabit (Gb) - 1,000,000,000 bits +1 terabit (Tb) - 1,000,000 bits + +## Etrhernet standards + +- Defined in the IEEE 802.3 standard in 1983 +- IEEE = Institute of Electrical and Electronics Engineers + +### Copper Ethernet standard + +| Speed | Common name | IEEE | Informal Name | Maximum Length | +| ------- | ------------------- | --------- | ------------- | -------------- | +| 10 Mbps | Ethernet | 802.3i | 10BASE-T | 100m | +| 100 Mbps| Fast Ethernet | 802.3u | 100BASE-T | 100m | +| 1 Gbps | Gigabit Ethernet | 802.3ab | 1000BASE-T | 100m | +| 10 Gbps | 10 Gig Ethernet | 802.3an | 10GBASE-T | 100m | + + +#### BASE T + +Base = refers to baseband signaling +T = twitsted pair + +### UTP Cables + +Unshielded Twisted Pair +Twisted mean that there sensitive against [[EMI]] Electronic Magnetic Interference +they got 8 pins + +10Base-T and 100Base-T = 2 pairs (4 wires) + +1000Base-T and 10GBase-T = 4pairs (8 wires) + +#### UTP Cables (10Base-T, 100 Base-T) + +Full-Duplex transmission +Both devices can send and received data at the same. no colission while occur + +##### Straight-through cable + + +Transmit 1 - 1 Receive +(TX) 2 - 2 (RX) +Recieve 3 - 3 Transmit + 4 4 + 5 5 +(RX) 6 - 6 (TX) + 7 7 + 8 8 + +##### Crossover cable + +Transmit 1 - 3 Transmit +(TX) 2 - 6 (TX) +Recieve 3 - 1 Receive + 4 4 + 5 5 +(RX) 6 - 2 (RX) + 7 7 + 8 8 + +##### Chart + +| Device Type | Transmit (TX) Pins | Recieve (RX) Pins | +| ----------- | ------------------ | ----------------- | +| [[Router]] | 1 and 2 | 3 and 6 | +|[[Firewall]] | 1 and 2 | 3 and 6 | +| [[PC]] | 1 and 2 | 3 and 6 | +| [[Switch]] | 3 and 6 | 1 and 2 | + + +##### Auto MDI-X + +allows devices to automatically detect and adjust the the pins for transmiting data prevent colissions + + +#### UTP Cables (10Base-T, 100 Base-T) + + +##### Straight-through cable + +Each pair is bidirectional + +the pair are + +1 and 2 +3 and 6 +4 and 5 +7 and 8 + +## Fiber-Optic Connection + +[[SFP]] Transceiver Small-Factor Pluggable for Fiber Optics cable + +Send light over glass fiber + +TX - RX +RX - TX + +there are 4 layers for this cable + +1 : the fiberglass core itself +2 : cladding that reflects light +3 : a protective buffer +4 : the outer jacket of the cable + +single-mode and multimode fiber + +### Multimode fiber + +- Core diameter is wider than single mode fiber. +- Allow mutiple angles (modes) of light waves to enter the fiberglass core +- Allows longer cables tha [[UTP]] but shorter cables than single-mode fiber. +- cheaper than single-mode fiber (due to cheaper LED-based SFP transmitters) + +### Single-Mode Fiber + +- Core diameter is narrower than multimode fiber +- Light enters at a single angle (mode) from alaser-based transmitter +- Allows longer cables than both UTP and multimode fiber +- More expensive than multimode fiber (due to more expnesive laser based transmitters) + +### Fiber-Optic cables standards + + +| Speed | Cable Type | IEEE | Informal Name | Maximum Length | +| ------- | ------------------- | --------- | ------------- | ---------------- | +| 1 Gbps | multi or single-mode| 802.3z | 1000BASE-LX | 550m(MM) 5km (SM)| +| 10 Gbps | Multi-mode | 802.3ae | 10GBASE-SR | 400m | +| 10 Gbps | Single-Mode | 802.3ae | 10GBASE-LR | 10km | +| 10 Gbps | Single-Mode | 802.3ae | 10GBASE-ER | 30km | + +## UTP vs Fiber-Optic Cabling + +- UTP + - Lower cost than fiber optic. + - Shorter Maximum distance than fiber0-optic (100m). + - Can be vulnerable to EMI + - RJ45 ports used with UTP are cheaper than SFP ports. + - Emit (leak) a faint signal outside of the cable, which can be copied (= security risk) + +- Fiber-Optic + - Higher cost than UTP. + - Longer maximum distance than UTP. + - No vulnerability to EMI. + - SFP ports are more expnsive than RJ45 ports (singl-mode is more expensive than multimode). + - Does not emit any signal outside of the cable (=no security risk) + diff --git a/03. How the TCPIP Model Actually Works.md b/03. How the TCPIP Model Actually Works.md new file mode 100644 index 0000000..a1dcba0 --- /dev/null +++ b/03. How the TCPIP Model Actually Works.md @@ -0,0 +1,118 @@ +--- +id: 03. How the TCPIP Model Actually Works +aliases: [] +tags: + - CCNA +--- +# How the TCPIP Model Actually Works + +## Protocols and Standards + +A [[Protocol]] is a set of rules defining how data should be communicated between devices over a [[network]]. + - The "Languages" that computers use to communicate. +Since the early days of computer networking, there have been several attempts to define the functions needed for computers +to communicate with each other + - Often developed by a specific vendor (e.g, [[IBM]]) to be used with their own products. + - With a proprietary approach, enabling communications between different vendor's products was difficult. +A [[standard]] is an agreed-upon specification that describes how a protocol or technology should work + - With vendor neutral standards, devices of all types can communicate with each others. + - An [[Apple]] Macbook can access a [[website]] hosted on a web server running [[Linux]]. + - A PC running [[WIndows]] can send an email that can be read on a smartphone running [[Android]] + +## A bit of history + +Early work on the computer netowrks that would evolve into today's [[Internet]] began in the [[1960]]s +- The [[US]] Department of Defense's [[ARPA]] funded ARPANET, which came online in 1969 to connect mainframes at universities and labs +- Originally used a protocol called [[NCP]] +Vint Cerf and Bob Kahn (working on DARPA) began developing [[TCP]] in 1974 +- Later divided into two protocols still used today: + - [[TCP]] + - [[IP]] +THese two protocols form the fundation of the protocol suite known as [[TCP/IP]] today + - ARPANET fully switched to TCP/IP in January 1, 1983. +TCP/IP became dominant over vendor-proprietary solutions at the time because it was published as a set of open +standards that any vendor could implement, and it could run over many different types of networks. + +## Who defines the standards? + +Most netwoking standards are developed by independent standards organizations, not by a single vendor, with participation from engineers at many companies +- [[IEE]] (Institute of Electrical and Electronics Engineers) + - Develops many of the technologies used on local area netowrks: + - [[Ethernet]] (802.3) + - [[WIFI]] (802.11) +- [[IETF]] (Internet Engineering Task Force) + - Open community that defines [[protocols]] used on the [[Internet]] + - [[TCP]], [[IP]], [[UDP]], [[HTTP]], [[DNS]], etc. + - Publishes standards in document called [[RFC]]'s (Requests for Comments) + +## Layered models + +Networks do a lot of different jobs to move data from one computer to another. + - Physical transmission of signals, local delivery on a [[LAN]], routing traffic between networks, end-to-end conversations, applications, etc. +A model lets us group related jobs into layers. + - Each layer has a specific role. + - Each layer uses the services of the layer below and provides services to the layer above +Protocol live (mostly at one layer) + - Examples later: IP, TCP, HTTP, etc. + - Together they form a stack of protocols that work as a team (the network stack) + +1. Application Layer : telnet, FTP, TFTP +2. Transport Layer: TCP, UDP +3. Internet Layer: IP, [[ICPM]] +4. Link Layer: cables, WIFI + +The model is description, not a law. + - Different textbooks/courses use slightly different models (4-layer, 5 layer...) + +## TCP/IP Layers + +### Layer 1 : the physical layer + +- The physical Layer (Layer 1) sends and receives bits as electrical, optical, or radio signals over the medium +- Defines things like cables, connectors, signal levels, and link speeds. +- Examples: copper UTP cables, fiber-optic cables, WI-FI radios and antennas, network interface cards [[NIC]]'s + - The physical aspects of transmitting data are very complex + +### Layer 2 : Local Network Layer + +- The Local Network Layer provides hop to hop delivery of messages on a local network. + - A hop is one step along the path between two devices: + - From one router or host, to the next router or host in the path + - [[Switches]] don't countL a switch just extends the local network, allowing multiple devices to connect. +- Uses [[MAC]] addresses to identify interfaces. +- Protocols at this layer includes + - Eternet + - Wifi + +### Layer 3 : The Internet Layer + +- The Internet Layer provides end-to-end delivery between hosts across multiple networks +- Uses IP addresses to identify hosts in the network. +- Routers operate mainly at this layer, using the message's destination IP address to forward the message toward its final destination host +- Protocols at this layer includes + - IP ([[IPv4]], [[IPv6]]) + - [[ICMP]] + +### Layer 4 : The Transport Layer + +- The Transport Layer provides end-to-end communication between application processes. + - Also called "process to process" or "service-to-service" +- Uses port numbers to identify the processes on each host. +- Runs mainly on the communicating hosts; routers normally operate based on IP, not on Transport layer informations +- Protocols at this layer includes + - UDP + - TCP + + +### Layer 5 : Application Layer + +- The application Layer is where network communications meet applications. + - Usually called Layer 7 +- Defines how application processes format, send, and interpret data +- Protocols at this layer define message formats and rules for specific tasks, such as: + - [[HTTP]]/[[HTTPS]] + - [[FTP]], [[TFTP]] + - [[SMTP]], [[POP3]] , [[IMAP]] +- Network infrastructure devices (routers, switches) don't care about Application-layer details. + - They just move messages across the network. + - Only the communicating hosts interpret the data diff --git a/04. Intro to the CLI.md b/04. Intro to the CLI.md new file mode 100644 index 0000000..08c7eaf --- /dev/null +++ b/04. Intro to the CLI.md @@ -0,0 +1,177 @@ +--- +id: 04. Intro to the CLI +aliases: [] +tags: + - CCNA +--- +# Intro to the CLI, Introduction to the [[CISCO IOS]] + +## How to connect to a [[Cisco]] device + +connect via a console port with [[RJ45]] or [[USB-mini]] +Use a Rollover cable + +## Terminal Emulator + +access with a Terminal Emulator (ex: PuTTy) + +default configuration: + +speed: 9600 +data bits: 8 +stop bits: 1 +parity: none +flow control: none + +## user Exec Mode + +User Exec mode is very limited. +Users can look at some things, but can't make any changes to the configuration. +also called 'user mode' + +```Cisco +Router> +``` + + +## Privileged Exec mode + +Provide complete access to view the device's configuration, restart the device, etc.. +Cannot change the configuration, but can change the time on the device, save the configuration, etc... + +```Cisco +Router>enable +Router# +``` + +## ? "list command available" + +for the full list of all the command available just type *?* + +```Cisco +Router>? +Router#? + +// to display abiguous command +Router>e? +enable exit +``` + +## Global configuration mode + +To enter configuration mode + +```Cisco +Router#configure termianl +Router(config)# + +//shortcut + +Router>enable +Router#con? +configure connect +Router#conf t? +terminal +Router#conf t +Router(config)# +``` + + +## Enable password + +To enable password in the config mode +**passwords are case-sensitive** +if you type 3 time a false password it exit + +```Cisco +Router (config)# enable password |your password| +// ex: +Router (config)# enable password CCNA +Router (config) #exit +Router>enable +Password: +Router# +``` + +## Running-config / startup-config + +There are two separate configuration files kept on the device at once. + +- *Running-config* : the current, active configuration file on the device. +As you enter commands in the CLI, you edit the active configuration. +- *Startup-config* : The configuration file that will be loaded upon restart of the device. + +### Show running-config/ show startup-config + +```Cisco +Router#show running-config + +Router#show startup-config +``` + +## Saving the configureation + +there are three ways to save the running configuration to the startup-config + +```Cisco +//1. +Router#write + +//2. +Router#write memory + +//3. +Router#copy running-config startup-config +``` + +## Service password-encryption + +for security purpose always save the password with password-encryption enable + + +```Cisco +Router (config) # service password-encryption + +//when using the show running-config it return +enable password 7 |hash of the password| +``` + + note: the number 7 is the type of encryption used for the encryption + 7 is the proprietary Cisco encryption [[algorithm]] + with the first method is easy to decrypt the password with a deencryption tool + +## Enable secret + +for more security use the method enable secret + +```Cisco +Router (config) #enable secret |Your password| +ex: +Router (config) #enable secret Cisco +//when using the show running-config it return +enable secret 5 |hash of the password| +``` + + note : number 5 is the number for the [[MD5]] encryption + +### sercice password-encryption + +if you enable service password-encryption + - current passwords will be encrypted + - future passwords will be encrypted + - the enbalbe secret will not be effected +if you disables service password-encryption + - current passwords will not be decrypted + - future passwords will not be decrypted + - the enable secret will not be effected + + +## Canceling commands + +for canceling a command with the device type *no* + the name of the command + +```Cisco +Router (config) #no service password-encryption +``` + + diff --git a/05. Ethernet LAN Switching.md b/05. Ethernet LAN Switching.md new file mode 100644 index 0000000..2165160 --- /dev/null +++ b/05. Ethernet LAN Switching.md @@ -0,0 +1,111 @@ +--- +id: 1772845705-JEBL +aliases: + - Ethernet LAN Switching +tags: [] +--- + +# Ethernet LAN Switching + +## [[OSI model]] - physical layer + +- Defines physical characteristics of the medium used to transfer data between devices +- For example, [[voltage]] levels, maximum transmission distances, physical connectors, cable specifications, etc.. +- Digital [[bits]] converted into electrical (for wired connections) or radio (for wireless connections) signals +- All of the information in day 2 [[02. Interfaces and Cables]] (cables, pin layout, etc.) is related to the Physical layer. + +## OSI model - Data Link Layer + +- Provides node-to-node connectivity and data transfer (for example, PC to switch, switch to router, router to router) +- Defines how data is formatted for transmission over a physical medium (for example, copper UTP cables) +- Detects and (possibly) corrects Physical Layer errors. +- Uses Layer 2 addressing separate from Layer 3 addressing +- Switches operate at Layer 2. + +## OSI Models - PDUs + +Layer 4 header - Data +Layer 3 header - Segment +Layer 2 header - Packet +Layer 1 header - Frame + +Protocol Data Units | PDUs + +## Ethernet Frame + +ethernet header | Packet | Ethernet Trailer + +### Ehternet Header + +Preamble | Start Frame Delimiter (SFD) | Destination | Source | Type or Length + 7 bytes 1 byte 6 byte 6 byte 2 bytes + +#### Preamble + +- Length : 7 Bytes (56 bits) +- Alternating 1's and 0's +- 10101010 * 7 +- Allows devices to synchronize their receiver clocks + +#### SFD + +- Start Frame Delimiter +- Length: 1 byte (8 bits) +- 10101011 +- Marks the end of the preamble, and the beginning of the rest of the frame + +#### Destination & Source + +Indicate the devices sending and receiving the frame +- Consist of the desination and source [[MAC Address]] +- MAC = Media Access Constol +- = 6 byte (48-bit) address of the physical device + +#### Type / Length + +- 2 byte (16-bit) field +- A value of 1500 or less in this field indicate the LENGTH of the encapsulated packet (in bytes) +- A value of 1536 or greater in this field indicates the TYPE of the encapsulated packet (Usually [[IPv4]] or [[IPv6]]) +and the length is determined via other methods + +IPv4 = 0x0800 ([[hexadecimal]]) +(2048 in decimal) +IPv6 = 0x86DD (hexadecimal) +(34525 in decimal) + +### Ethernet Trailer + +Frame Check Sequence (FCS) + 4 bytes + +#### Frame Check Sequence + +- 4 bytes (32 bits) in length +- Detects corrupted data by running a 'CRC' algorithm over the received data +- CRC = Cycling Redundancy Check + +## Mac Address + +- 6-byte (48-bit) physical address assigned to the device when it is made +- AKA ' Burned-in Address' (BIA) +- Is globally unique +- The first 3 bytes are the OUI (Organizationally Unique Identifier), which is assigned to the company making the device +- The last 3 bytes are unique to the device itself +- Written as 12 hexadecimal character + +Unicast frame: a frame destined for a single target + +### Dynamically learned Mac Address + +Is a mac address learned by the switche automatically by looking at the frame Destination Frame + +if the Mac address is not in the switch mac address table it will flood the frame (send the frame at all the interfaces except the source mac address) +until the PC replied to another pc +**Unknown Unicast Frame** -> *Flood* + +if the Mac address is knowned by the switch it will directly send it in the interface +**Known Unicast Frame** -> *Forward* + +*Dynamically Mac Addresses are removed from the MAC address table after 5 minutes of inactivity* + + diff --git a/README.md b/README.md index 0d6c3b4..4d0e3ac 100644 --- a/README.md +++ b/README.md @@ -1,16 +1,9 @@ # CCNA Notes -All my notes for passing the CCNA exam +All my notes for passing the CCNA exam (based on Jeremy ’s IT Lab) -The **Cisco Certified Network Associate (CCNA)** is a -widely recognized entry-level IT certification that validates -a professional’s understanding of networking fundamentals. -It covers key topics such as network access, IP connectivity, -security basics, automation, and troubleshooting. -CCNA is designed for individuals starting a career in -networking and provides a strong foundation for roles like network technician, -support engineer, or junior network administrator. +This repository contains my structured notes from studying +the Cisco Certified Network Associate (CCNA) using Jeremy's IT Lab. +It covers essential networking concepts including network fundamentals, +IP connectivity, network access, security basics, automation, and troubleshooting. -## Free CCNA 200-301 Complete Practical Course V1.1 by David Bombal Tech - -[Link to the video](https://youtube.com/playlist?list=PLw6kwOJVj3MbMZ8B72ZgUryj8OSETC0ds&si=8JAireGwkWrVzHbe)