What's the Difference Between a Static and a Dynamic IP Address?
The IP address
from your ISP
is assigned one of two ways:
1) Set to an IP address which is unchanged for months or years at a time. This is a static IP address.
2) Set to an IP which is only good for a limited time, and which is changed according to the policy set by your ISP's DHCP server. This is a dynamic IP address.
Because a static IP can be relied on for an indefinite period, some networking software requires a static IP.
ISPs usually charge extra for static IPs. Your ISP may not be willing to give their customers static IP addresses at all.
Dynamic IPs are used in large networks where computers are frequently reconfigured,
or where a limited number of IP address are available to share between many computers.
Dynamic vs Static IP Addresses
There are two methods to assigning IP addresses
to computers: dynamic and static.
Static IP addresses are used primarily for servers so that they don't appear to "move" while non-servers are usually assigned dynamic IP addresses.
Most dynamic IP address
users are users of internet service providers (ISPs) since not all the users of an ISP are online at one time
and the ISPs can "get away" with not having enough IP addresses for each user.
In order to use a dynamic IP address, a service such as Dynamic Host Configuration Protocol (DHCP)
is used to assign addresses dynamically
to devices as they request them. If a static address is used, it must be manually programmed into parameters of the device's network interface.
(It is also possible to "fake" static IP address assignments through DHCP by assigning the same IP address to a computer — and no other — each time it is requested.)
Dynamic or Static IP Addresses
When you don't need static IP addresses:
When you need Static IP Addresses:
- If you browse the Internet.
- If you send and receive e-mail via an offsite server (the normal method).
- If you download or upload files.
- If you use Instant message services or chat services.
- You run one or more Web server's directly on your site that require external access.
- You run one or more FTP server's directly on your site that require external access.
- You run one or more E-mail server's directly on your site that require external access.
- You allow 'incoming' Video Conferencing you may need to use static IP addresses.
- You run any other service or 'Application' that requires external access. For example some peer-to-peer, game applications require that you have a static IP address for licensing purposes.