High packet drop rate from ACL blocking indicates misconfigured access controls
warningsecurityUpdated Jan 28, 2026(via Exa)
Technologies:
How to detect:
Packets are being dropped due to Tailscale access control rules, indicated by the 'acl' reason label in dropped packet metrics. This suggests ACL rules may be blocking legitimate traffic.
Recommended action:
Review Tailscale access control policies in the tailnet policy file. Check tailscaled_inbound_dropped_packets_total and tailscaled_outbound_dropped_packets_total metrics filtered by reason='acl'. Update ACL rules to allow necessary traffic while maintaining security posture.