Network Jounal - DefiantCoder/Tech-Journals GitHub Wiki

7.Application ⇒ 6.Presentation ⇒ 5.Session ⇒ 4.Transport ⇒ 3. Network ⇒ 2. Datalink⇒ 1. Physical Application layer Network: The data being sent/received by the computer

Presentation layer Network: Compression, encryption, other encoding

Session Layer Network: Session setup and teardown

Transport Layer Network: Port numbers tell receiver what application the data is for

Network Layer Network: IP address of sender and receiver

Datalink Layer Network: Defines how the packets get onto the media Switches work at this level

Physical Layer Network: Physically send the bits over media

Devices on LAN can only communicate “NIC-to-NIC”

NICs will only pay attention to packets with it’s own MAC address as the Destination MAC Topology is the network architecture

The first 6 identify the manufacturer (organizational Unit Identifier) and the last 6 are unique identifiers of the device (Unique Device Number)

IP address is a 32-bit number

Hubs are “dumb” Layer 1 Devices that don't read packet addresses

Address Resolution Protocol (ARP), Layer 2 protocol is used to resolve an ip address to a hardware address for final delivery of data packets to the destination.

Operating systems use ARP Cache to store the MAC address of recently resolved IP addresses

arp = command will show info on the cashe

            The systems send an ARP request to the Default Gateway

The Layer 2 Header (Source and Destination MAC) are always addressed for direct NIC-to-NIC communication So even if the packet is intended for Google, the destination MAC will always be the next NIC As a packet crosses networks - the Layer 3 Header (IP) stays the same but The Layer 2 Header (MAC) is re-written as it crosses each router

Subnet mask 255.255.255.0 - the octet goes up to 255 a 32 bits address used to distinguish between a network address and a host address in IP address, it is not shown in data packets traversing the internet

#9/3/21 ipconfig, ping, tracert, nslookup To find the command prompt you can search it in the bottom search bar or windows key + x

ipconfig = provides the computer's DNS Suffix, IPV6, IPv4, Subnet Mask & Default Gateway by simply typing ipconfig you can access this information

ping = allows you to send a hello and see what is connected by typing ping plus an IP address you can ping it and see if it is connected

tracert = allows us to see the number of hops (ip and sometimes description) between the computer and the searched site and the time taken Enter tracert + url in question

nslookup = allows us to discover the number of IP address owned by that name and its true name enter nslookup, press enter then enter the site in question

deploy workstations and switches in Packet Tracer -To do this you select the workstation or Switch option and choose from the displayed options then drag and drop the selection

How do you connect these devices with cables? -By selecting the cable of choice you click on one device, and choose the desired connection option, then repeat the process for the other device

How do you access the command-line terminal on a Packet Tracer PC? -You select the pc then go to desktop ⇒ command prompt and there you go

Assigning IP address to a PC in Packet Tracer select the PC ==> config ==> FastEthernet ==> enter your IP address

What is a MAC address and its components? -The MAC address is the unique identifier for the device and is divided into two parts, the first 6 characters denote the manufacturer whereas the last 6 identifies the specific device used

How to get a MAC address -If it is the current terminal type ipconfig/all

What is Wireshark & how to use it -Wireshark tracks the incoming and outgoing packet traffic for the device, and can be used to denote what websites, how often, the mac addresses and other information

Finding a protocol in Wireshark -There is a search bar at the top of the terminal that can be used to find specific protocols

How to dump your arp cache in linux -ip -s -s neigh flush all

How to Dump an arp cache -Arp -d This is useful to slim traffic and find your the specific arp you are looking for.

9-25-21 How do you set the gateway address on a workstation in Packet Tracer? -select the PC ==> config ==> settings ==> gateway textbox

How do you set the IP and subnet mask on different interfaces of a multilayer switch? -Select the switch ==> config ==> FastEthernet 0/x x == the desired interface

How do you enter simulation mode in Packet Tracer? -On the bottom right corner select the simulation option

How do you set which types of packets you want to see in Simulation Mode? -The edit filters option allows you to customize what you will see in the simulation.

How do you find the MAC address table? -click on switch => CLI => type enable to enable admin mode (exit will exit it) => type 'show mac-address-table'

Document the use of "Simulation Mode" -Simulation mode can be used to discover issues, track traffic and visualize what is happening in your network

Document how to save configurations on routers -From Router=> Config Tab => Save NVRAM

Enter useful Packet Tracer Tips/Tricks you pick up

Fast foward is useful, the lightning bolt speeds up connecting devices, use blank switches to keep track of everything ##ALWAYS MAKE SURE DEVICES & PORTS ARE ON##

How did you connect to a router?

by using the auto connect cables and setting the correct ip addresses on it in conjunction with the correct default gateways it successfully connected

Subnetting Basics:

The first IP in a subnet is the Network Address & the last is the Broadcast Address.
The first USABLE IP is one after the Net Address & the last USABLE IP is one before the Broadcast
the range starts at 0 then goes to 31 or 63 or 95 (this makes 32, 64, 96 IPs total)
the size of the subnets is determined by the number of subnets required
The CIDR can help us know the number of Total hosts & Usable hosts

10/9/21 Lab 6-1

RIP defines how routers should share information when moving traffic among an interconnected group of LANs
Serial Connections need the same clock speed to work

How to use Simple PDU?

This function can be executed by selecting the closed envelope icon and selecting the sender and receiver, this is a quicker way to ping and test your connections

When connecting two routers make sure both are on and on the same settings. make sure to double check the addresses in case of mistype.

How to enter Config Mode?

Select the router / go to CLI / type 'enable', then 'config terminal'

What is Show IP route?

command 'show ip route' can be done on a router that does not have the command 'enabled' on and will show what is connected and through what port those connections are made

ip route- (EX. ip route 192.168.30.0 255.255.255.0 10.10.10.1)

This command can make connections for the router through the interface

connecting routers (in CLI) Enable Configure terminal Interface serial2/0 Ip route default gateway subnet mask (router’s) router IP

Static routing tip When connecting routers together make sure the correct ip's are entered in and everything is properly filled in.

Enabling rip

enable => configure terminal => router rip => version 2 => network xx.xx.xx.xx (default gateway) => network xx.xx.xx.xx (ip for the router)