Allowing the Public Internet to Connect to your Computer
Glossary of Terms
The following terms accompany a tutorial series on making your computer accessible from the public internet.
Dynamic Host Configuration Protocol. A process where Internet Service Providers (ISPs) assign IP addresses to computers on an as-needed basis. This helps conserve the limited number of IP addresses available, but it means that your computer won't always be available at the same IP address.
Domain Name System. This is a service that automatically associates a computer's IP address with a domain name, making it an excellent solution to dynamic IP address problems.
Software or hardware that acts as a barrier between a local area network (LAN) and the Internet. A firewall prevents unauthorized connections from being made to any device on the LAN, protecting information, files, and computer functions that would otherwise be susceptible to hackers, viruses, or other mal-intentioned activity.
There are two types of IP addresses: Static and Dynamic. A Static address doesn't change, and your router has to be manually assigned to the address. A static address is needed when you are using your computer as a server, where you or your clients must be able to access data on your computer from a remote location. A Dynamic address is assigned by an ISP on an as-needed basis, or any time your computer attempts to connect to the Internet, and is obtained through a router. A dynamic address works well for users who simply check email and surf the Internet.
An Internet Service Provider is a company that sells Internet access to its customers. ISPs can offer Internet connections through cable, telephone, satellite, etc.
Local Area Network. Refers to a small network of computers and devices found in places such as a home or a small office, usually with at least one device connected to a router for Internet access.
Network Address Translator. NAT routers take the public IP address for themselves and then assign local IP addresses for any computers or devices on the network, allowing all the computers and devices to share the public IP address. The downside of this setup is that anyone looking for information on a computer inside the network will reach the router, not the desired computer, unless the router has been configured to allow access.
IP addresses are divided into ports, so that a single IP address can be used for multiple connections. Ports can range in number from 1-65535, though some port numbers are reserved for common uses. For example, HTTP uses port 80, and email uses port 110.
Simple Traversal of User Datagram Protocol Through Network Address Translators. STUN is used to keep a connection open for programs using UDP, such as VoIP, that are behind a NAT router, and is only available in applications that use STUN.
Transmission Control Protocol, meaning when one computer attempts to talk to another, they must acknowledge each other (or handshake) before data transmission can proceed. TCP is often used for emailing and file transferring.
User Datagram Protocol, meaning when one computer attempts to talk to another, no acknowledgement (or handshake) is needed. This type of connection is less reliable than TCP, but is often used for VoIP and gaming applications.
Universal Plug and Play allows devices and software applications to configure their network settings automatically with a router, saving the user from the hassle of manually configuration to ensure proper setup.
Wide Area Network. Refers to a large network that spans over a large area, such as cities and countries. WANs are used to connect localized networks together. The most familiar example of a WAN is an Internet Service Provider (ISP).