How to Block Callers with No Caller ID on VoIP

Anonymous or "no caller ID" calls can be a nuisance. Most hosted VoIP systems let you block or screen them.

Using Call Blocking Rules

In your VoIP admin portal or phone settings, look for "call blocking", "anonymous call rejection", or "privacy" options. Enable blocking of calls that withhold their number (CLIR/private).

Auto Attendant and IVR

Some systems route anonymous callers to a different queue or require them to enter a digit before connecting. This filters out many automated calls.

Allowlist Important Numbers

If you block all anonymous callers, ensure key contacts (e.g. hospitals, schools) are in an allowlist so their calls still get through.