Filter
Top Products
rent them in blocks. If, like most broadband Internet users, you have a service provider who assigns you a
temporary IP Address and changes it from time to time, then you will need to sign up for a Dynamic DNS service.
What is the difference between a Static and Dynamic IP Addresses?
IP Addresses are the numbers used by the Internet Protocol(IP) to identify your computer or device. Every
computer or device that wants to communicate over the Internet must have an address, unique to that computer
or device. Internet Service Providers can issue IP Addresses in two ways;
Static assignment: This is simply determining the address to be used and (usually manually) entering it into the
computer or device. The number will not change, and may not be used by any other device.
Dynamic assignment: This utilizes a protocol calls Dynamic Host Configuration Protocol (DHCP) that generates
an IP Address and leases(i.e. provides) it to your computer or device for a predetermined length of time. After
that time expires, your computer or device must request a new IP Address. There is usually no guarantee that
the new IP Address will be the same as the old one, and in many practical instances it isn't.
What is the difference between an internal and an external IP Addresses?
Every device that communicates over the Internet must have a unique IP Address. These are all external, or
public, IP Addresses. However, there are ranges of IP Addresses that are excluded from this address space, so
that they can be used internally by devices connected via Local Area Networks. These are internal, or private, IP
Addresses. If devices that are using internal addresses wish to communicate with devices on the Internet, they
must pass their messages through a network gateway, which will map the internal IP Addresses into a valid
external IP Address. This is called Network Address Translation (NAT), as shown in the following figure.
Figure 4: Example of Network Address Translation
6
Gateway/Router
Device
IP Address in msg
on the Internet
from: 216.176.57.75
to: 216.099.34.23
IP Address in msg
on the LAN
from: 192.168.1.55
to: 216.099.34.23
Internet
LAN