OS X Mountain Lion: Use a dynamic global hostname
If your service provider supports secure dynamic DNS update (RFC 3007), you can give your Mac a global DNS hostname so other computers outside your local network can refer to it by name.
Even if your computer’s IP address changes at regular intervals, your computer will automatically update its global DNS hostname to point to its current IP address.
- Choose Apple menu > System Preferences, and then click Sharing.
- Click Edit, and then select “Use dynamic global hostname.”
- Enter the hostname, user name, and password for the account.
Ask your service provider or domain administrator for the user name and password so your Mac can update its hostname every time its address changes.
- If your service provider supports Wide-Area Bonjour registrations, you can also select “Advertise services in this domain using Bonjour” to advertise your computer’s active Sharing services in its domain.
If Bonjour browsing is enabled for this domain, other computers will see the services listed automatically in their apps, based on the Search Domains entered in their Network preferences or based on information returned by DHCP.