Failsafe rules
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 |
| 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.