Network security groups should limit inbound TCP port 21 access from the internet
The Powerpipe check verifies that Azure network security groups are set to restrict inbound `TCP` port `21` access from the internet. Trivy rule `AZU-0047` also flags unrestricted ingress from any IP address in a security rule.
Opening up ports to allow connections from the public internet is generally to be avoided. You should restrict access to IP addresses or ranges that are explicitly required where possible.
What this control checks
Network security groups should restrict inbound TCP port 21 access from internet
Audit evidence
Evidence that deployed resources meet this control: PowerPipe control azure_compliance.control.network_security_group_restrict_inbound_tcp_port_21.
Scans of the Terraform code that flag the same setting before deployment: Trivy check AZU-0047.
Related controls
Tool mappings
Use these identifiers to cross-reference this control across tools, reports, and evidence.
- Compliance.tf Control:
network_security_group_restrict_inbound_tcp_port_21 - Powerpipe Control:
azure_compliance.control.network_security_group_restrict_inbound_tcp_port_21 - Trivy Check:
AZU-0047
Last reviewed: 2026-10-13