Networking terminology glossary
January 21, 2025
Disclaimer:
These are just concepts I’ve learned and can reference every now and then in no particular order. The definitions are my own interpretation and may or may not be 100% accurate. This page is more a journal than a source of truth.
- WAN port
- The port on a router or switch that is used to connect to the internet.
- LAN port
- The port on a router or switch that is used to distribute a connection to attached devices.
- VLAN
- A method of segregating LAN ports into independent network streams. This way you can for example isolate IoT devices or any other devices from the rest of the network in order to protect the entire network in case of a breach.
- Gateway
- The entrypoint and the exit route for a network that is communicating with the internet. The gateway usually is assigned to the first available address of a subnet.
- Subnet
- A range of IP addresses.
- DNS
- A system that resolves address names to IPs.
- Subnet Mask
- A subnet mask annotates the way addresses can be assigned to devices on a network. It allocates the network and the host bits of a subnet. A common subnet mask in home networks is 255.255.255.0 which essentially allows for 254 assignable IPs in the given subnet.
- CIDR
- CIDR is essentially a shorthand annotation of a subnet mask, indicating which bits are reserved to the network. So to represent a subnet mask of 255.255.255.0 an example subnet would be annotated with 192.168.1.0/24 which indicates that only the last 8 bits will be used to assign IPs to clients on the network.
- DNS round robin (semi-failover)
- If you assign 2 IPs to the same DNS record, clients will randomly receive one of the 2 IPs in a very basic attempt of load balancing.
- DynDNS
- Dynamic DNS is the method of automatically reassigning an IP to a DNS record so if the target host's IP address changes, the services remain reachable.