A Dynamic DNS service allows the user to alias a dynamic IP address to a static hostname in any of the many domains, allowing a computer to be more easily accessed from various locations on the Internet (without the need to remember a possibly frequently, changing public IP address.
The Dynamic DNS is ideal for a home website, file server, or just to keep a pointer back to a home PC so the user can access those important documents while at work. Using one of the available third-party update clients the hostname can be kept always pointing to the public IP address, no matter how often the ISP changes it. No more fumbling to find the IP address, or e-mailing everyone every time it changes. Just notify the users of yourname.dynamic.dns.org instead!
Typically client software will be set up on either the local router or one of the computers on the LAN to periodically check the Public IP address. When the Public IP address changes this client will notify the Dynamic DNS service of the change and this service will in turn update the IP address that the yourname.dynamic.dns.org hostname directs to.
There are a number of providers of such services and they usually offer at least a basic service for free. Examples include, but are not limited to:
| Service | URL | Comments |
| DynDNS | www.dyndns.org | Basic service, for up to 5 free hostnames |
| No-IP | www.no-ip.com | No-IP Free: basic dynamic DNS and web redirection service |
Guidance on setting up client doftware for each of these services, in a Linux environment, are available from: