rhnsd is the Red Hat Network Daemon. Every other hour, it sends a request to Red Hat Network (RHN) asking for any notifications or updates and works in coordination with Red Hat Network to schedule automated tasks.

It sends information to Red Hat Network only requested by you. If you add a new system using the Red Hat Network web interface, the next time the Red Hat Network Daemon probes Red Hat Network it receives a request to return the information you requested as part of your System Profile, such as what package versions are installed on your system.