Networking Terms and Definitions

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Port Forward Staff
July 18, 2017 (Last Updated: ) | Reading Time: 4 minutes

Key Networking Terms

Here are some important terms and definitions to help you on your quest to understand more about networking.

Domain Name - A domain name is the web address that you type into your browser when you want to view a webpage. Some domain names that you may already be familiar with are google.com and amazon.com. This site's domain name is PortForward.com.

DNS - The DNS (Domain Name System) servers translate a web address into the numerical IP address of the server that is hosting the website. In other words, they translate the website name into a number.

For example, if you type PortForward.com into your web browser, your computer needs to know what IP address corresponds to PortForward.com.

Your browser sends a query to the system of DNS servers to find PortForward.com.

The DNS servers respond with the IP address.

Finally, your browser can then send a request to that IP address to retrieve the contents of the website.

Gateway - Usually this is your router. When you talk about your gateway, generally you are talking about the IP address that your router uses. When you specify gateway in your TCP/IP properties you are entering the IP address of your router. If you enter your gateway into the address bar of your browser, you will get the web interface of your router. (This should take you to your router's welcome screen, unless you have an apple router.)

NIC - Network Interface Card. This is a card in your computer that allows you to connect to routers, switches, and modems via ethernet. It's the card that your network cable plugs into.

TCP/IP - This is the protocol your computer uses to communicate with servers on the internet, and devices within your network. In Windows, this portion of your network properties allows you to define an IP address, subnet mask, gateway, and DNS servers.

Private (internal) IP Address - If you are using NAT, every device on your network has an internal IP address. Internal IP addresses are provided by your router. Your entire network can see the internal IP addresses for your devices. Devices outside of your network (or devices on the internet) cannot see them because your router "hides" private IP addresses.

Public (external) IP Address - Every device or server that has a public IP address is directly connected to the internet. Usually DLS/cable routers are assigned a public IP address by the ISP they are connecting to.

Dynamic IP Address - "Dynamic" relates to how routers assign IP (Internet Protocol) addresses to devices on your network. Your router assigns an IP address to each device on your network. Every time a device on your network is rebooted, its IP address can change. In order to forward ports in your router, you must specify an IP address to forward the ports to.

When forwarding ports, you should have a static, not dynamic, IP address so that your forwarded ports continue to work. Without a static IP address, the IP address on your device can change and cause your forwarded ports to just quit working.

Static IP Address - When you assign a static IP address (in your router) to a device on your network, it ensures that the IP address remains the same even after powering off the device. When you power the device back up, it will still be assigned to that same IP address. However, if you assign a static IP address to a device on your network, and you leave DHCP enabled on your router, then you may have problems. For more information on assigning static IP addresses visit our Static IP page.

NAT - When your router is using NAT (Network Address Translation), it is taking data from one public IP address, and breaking that data into multiple private IP addresses.

Data is sent to your network on a public IP address, from the internet.

Using NAT, your router then directs that data to multiple internal private IP addresses. NAT basically breaks one IP into many.

There is a problem with it though. When a device on the internet requests data from a device on your network, your router does not know which internal network device to get the data from.

This is where port forwarding comes in. Port forwarding tells your router which internal device to get the data from when it sees requests on specific ports.

Port Forwarding - Forwarding a port allows certain traffic from the internet to enter your network through your router. Forwarding ports in your router directs the incoming data through those specific ports to the IP address of a private device on your network.

Port Triggering - Allowing your router to dynamically open up ports, when it sees data on other ports. Port triggering allows you to do port forwarding, but only have the ports open when you are running the application. So you open up a program. That program then sends data out on outgoing ports called trigger ports. Your router sees data leaving your network on these ports. The router then allows incoming data on the ports specified in your port triggering configuration. When the router no longer sees data going out on the trigger ports, it turns off access to the incoming ports.

Subnet Mask - The subnet mask is part of your IP address configuration. The subnet tells your computer which group of IP addresses you belong to. For more information on subnet masks visit our Subnetting page.

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