Failsafe rules

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To avoid completely cutting off a host via incorrect or malformed policy, Calico has a failsafe mechanism that keeps various pinholes open in the firewall.

By default, Calico keeps the following ports open on all host endpoints:

Port Protocol Direction Purpose
22 TCP Inbound SSH access
53 UDP Outbound DNS queries
67 UDP Outbound DHCP access
68 UDP Inbound DHCP access
179 TCP Inbound & Outbound BGP access (Calico networking)
2379 TCP Inbound & Outbound etcd access
2380 TCP Inbound & Outbound etcd access
6443 TCP Inbound & Outbound Kubernetes API server access
6666 TCP Inbound & Outbound etcd self-hosted service access
6667 TCP Inbound & Outbound etcd self-hosted service access

The lists of failsafe ports can be configured via the configuration parameters FailsafeInboundHostPorts and FailsafeOutboundHostPorts described in Configuring Felix. They can be disabled by setting each configuration value to “none”.

Important: Removing the inbound failsafe rules can leave a host inaccessible.

Removing the outbound failsafe rules can leave Felix unable to connect to etcd.

Before disabling the failsafe rules, we recommend creating a policy to replace it with more-specific rules for your environment: see Creating policy for basic connectivity.