What it is
Secure tunnels such as OpenVPN, IPsec, WireGuard.
Why it is risky
Public by design, but outdated protocols (PPTP) and unpatched gateways become an entry path.
What to do
Keep protocols/patches current, enforce MFA, and retire PPTP.
Is it listening on your server?
Linux
ss -ltnp 'sport = :500'Track these versions on your own servers
InfraGuard collects installed software versions from every server and flags the ones with known vulnerabilities. Self-hosted — nothing leaves your network.