Closing Port 111 (rpcbind)

The Issue

Port 111 (rpcbind service) was accessible from the internet. This creates two main risks:

• DDoS reflection attacks
• Network reconnaissance by attackers

The BSI regularly scans for such vulnerabilities and notifies providers automatically.

The Fix

Since my Proxmox Backup Server doesn’t need NFS functionality, simply disable rpcbind:

systemctl stop rpcbind.service
systemctl stop rpcbind.socket
systemctl disable rpcbind.service
systemctl disable rpcbind.socket

Verify

Check the service is stopped:

systemctl status rpcbind.service
ss -tuln | grep :111