Local Area Network
A single home or office network
Wide Area Network
Linking multiple resources or LANs - Multiple office networks
Metropolitan Area Network
Linking multiple LANs - SOC, school networks, city networks
All computers are connected to a single cable
Antiquated process - still used in broadcast media
Each node is connected to a switch
Most common network setup you will see
Each node is connected to one other. Reduces chances of packet collision
Rarely seen outside of a MAN or ISP datacenter-to-datacenter connection
Each node has an independent connection to every other node on the network
Used by MSPs and ISPs for highly-available and fault tolerant networks.
Network Cables - Copper
Max data transfer speed
Max Operating Length
Network Cables - Fiber
OM1 - Orange Jacket
10 Gbps/33 Meters
100 Mbps Ethernet
OM2 - Orange Jacket
10 Gbps/82 Meters
1 Gbps Ethernet
OM3 - Aqua Jacket
10 Gbps/300 Meters
10 Gbps Ethernet
OM4 - Aqua Jacket
10 Gbps/400 Meters
100 Gbps Ethernet @ 150 meters
OM5 - Green Jacket
10 Gbps/400 Meters
Improvements on OM4. It breaks down light wavelengths more efficiently.
OS1 - Yellow Jacket
up to 100 Gbps/10 km
Single mode fiber for connecting indoor nodes. Used in fiber internet connections and datacenters.
OS2 - Yellow Jacket
up to 100 Gbps/200 km
Single mode fiber for connecting infrastructure outdoors. Used for MANs, ISPs, or MSPs.
7 Layer OSI Model
End User Layer
HTTP, FTP, SSH, DNS
SSL, SSH, IMAP, MPEG, JPEG
Sync & Send Layer
IP, ICMP, IPSec, IGMP
Ethernet, PPP, Switch
Fiber, Access Points, Copper Cabling
ip -br -c link
Is your physical interface up? Gives you detailed information on your NICs and virtual NICs.
ip neighbor show
Displays the Address Resolution Protocol (ARP) table. Shows the IP and MAC addresses of computers you can reach on the network.
ip -br -c address show or
ip -br -c a'
Displays your network cards, their connection status, the IP address and CIDR. Make sure you have a valid IP address on your LAN NIC.
ping <website or IP address>
Ping the device you're trying to connect to, or ping a commonly used server like Google's DNS (188.8.131.52) .
traceroute <website or IP address>
Sends a packet out to a destination using Time to Live (TTL). The end result is a list of routers that the packet interacted with on the way to the destination
ns lookup <website name>
Checks recognized DNS entries on your server. Make sure the IPs match up with results from ping
Socket Statistics gives you a list of connections and ports on your server. Use it to make sure you are able to connect to certain devices
-t Show TCP ports
-u Show UDP ports
-n Do not try to resolve hostnames
-l Show only listening ports
-p Show processes that are using a particular socket
-4 Only show IPv4 sockets
SSH or RTP
Get a device to accept your SSH session or initialize an RTP session from a camera. Keep in mind, RTP is different from RTSP.
Connect to a camera's webpage, or query a camera stream through VLC.
Using the program
Can you interact with a webpage? Can you view DS logs once it's running? Good! Then you've confirmed the Application is up and running.
Prevents unauthorized access into a LAN.
"The wifi" - That little black box that people have near their TVs that they call: the internet. This will be the handoff from an ISP to your LAN or firewall.
Provides compatibility between different networks.
Forwards data packets between different networks. They "direct traffic" typically received from outside networks.
Connects devices together by using packet switching. Used for internal traffic.
Wireless Access Point
The Wifi! This allows wireless devices to connect to a network rather than plugging into a switch directly.
You plug your computer into a wall port. The wall port is connected to a patch panel. The patch panel connects to the switch. This prevents a tech from running new cables through a wall every time a computer joins the network.
Network End Stations
Network Interface Controller (NIC)
The ethernet jack on a computer.
Wireless Network Interface Controller
Same thing as a NIC, but it uses radio waves to connect to an access point instead of a cable.