Internet Protocol addresses are 32-bit binary numbers separated by periods that identify a computer, printer or other device on a network. The network in question may be your Internet service provider's or your company's. Devices that join the network are assigned static or dynamic IP addresses. Static IP addresses last the life of the computer or until it is explicitly changed by the network administrator; dynamic IP addresses are temporary. The differences between the two come down to address assignment, hardware and network configuration, usage and cost.
IP Address Assignment
A network or information services administrator assigns a static IP address to any device that joins the network. The IS administrator configures the computer's network settings so that every time the computer connects to the network, it uses the same IP address. Devices that connect to the network through Dynamic Host Configuration Protocol receives a dynamic, or temporary, IP address from a pool of available addresses an IS administrator has designated on a server. When the device boots and connects to the Internet, it sends out a "discover" message to the DHCP server. The DHCP server returns with an "offer" message. If the device accepts the offer, it returns a "request" message back to the DHCP server and the DHCP server then assigns a temporary IP address. Dynamic IP addresses change every time the computer boots and logs into the network.
In an environment with multiple devices, how these devices connect to the Internet depends on the IP address configuration. In addition to the DHCP server set up on the provider's end, a network that employs a dynamic IP address requires a DHCP-capable router and modem. Networks using a static IP address as the "host" require switches or hubs available to provide network connectivity to other devices residing on the network. Dynamic IP addressing is easier to implement and administer, especially when it comes to mobile devices connecting and disconnecting to the network. Administrative overhead is required to maintain static IP addresses.
How you use the Internet determines which type of IP address you select. If you use your devices to surf the Web, check email and upload or download files, then a dynamic IP address should suffice. A static IP address works best if you intend to operate servers, use VPN, participate in gaming, offer hosting applications or set up VOIP telephony equipment where a permanent address matters.
Overall, static IPs incur more overhead as IS administrators must keep track of devices and addresses. Assigning static IP addresses to devices that come and go, especially for networks that have limited IP addresses, can an inefficient use of resources. Because the address is always the same, devices that have static IP addresses quickly become security risks for data mining operators and hackers. Although dynamic IP addresses are easier to assign and cheaper to implement, they, too, have their limitations. The IP address becomes a moving target, as it changes each time a computer disconnects from and reconnects to a network. Because there is no guarantee the device can log on with the same IP address, this can wreak havoc on applications that need stable connections.
One additional advantage that dynamic IP addresses maintain over static IP addresses is its portability. Devices with dynamically-generated IP addresses that change networks and subnets may continue to connect and receive network resources. A device using a static IP addresses must be reconfigured each time it switches networks or subnets.
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