Internet-Security.com TCP port 5906 details

TCP 5906 is most commonly a VNC port: VNC servers listen on 5900 + display number, so display :6 uses 5906.
Real-world servers that can listen on 5906 include RealVNC, TightVNC, UltraVNC, TigerVNC, and x11vnc when started with display :6 or rfbport 5906.
On macOS, Vine Server (OSXvnc) can be configured to serve VNC on 5906.
Virtualization platforms expose VM consoles over VNC on 5900+n; QEMU/KVM (qemu -vnc :6), libvirt/virt-manager, Proxmox VE, and Xen commonly map a guest console to 5906.
VMware ESXi/Workstation can optionally enable a VNC server per VM on port 5900+n, which would be 5906 for display 6.
Web VNC frontends like noVNC often proxy to backend VNC servers listening on ports such as 5906.
Security note: exposed VNC services on ports 5900–5999 (including 5906) are frequently scanned and brute‑forced by attackers, especially when weak or no authentication is configured.

TCP 5906