A Raven cellular modem with a dynamic IP address can be addressed through the DDNS (Dynamic Domain Name System) offered as a free service by Sierra Wireless (AirLink). The service translates a dynamic IP address into a fully qualified domain name so that the modem can be contacted directly via the Internet as if it had a static IP. Campbell Scientific recommends that customers set up their Raven modems with a modem name that is the cellular phone number and that they use a domain of eairlink.com.