Internet-Security.com UDP port 497 details

Retrospect Backup (by Dantz/EMC/Retrospect Inc.) uses UDP port 497 for client discovery/advertising; Retrospect Clients on Windows, macOS, and Linux listen on UDP 497 so the Retrospect server can find them, while actual backup sessions typically use TCP 497.
The IANA service name for this is “retrospect” (historically “dantz”).
Security note: older Retrospect Client versions exposed vulnerabilities on the 497 port that enabled remote code execution, and public exploits (including Metasploit modules) have targeted this service.

UDP 497