nodetool invalidatecidrpermissionscache¶

Invalidates the CIDR permissions cache on the node.

Synopsis¶

nodetool [connection_options] invalidatecidrpermissionscache

Description¶

nodetool invalidatecidrpermissionscache clears the cached CIDR authorization decisions on the node. This forces re-evaluation of CIDR-based permissions for subsequent connection attempts.

The CIDR permissions cache stores the results of IP-to-CIDR-group lookups to improve authorization performance. Invalidating this cache is necessary after modifying CIDR groups to ensure changes take effect immediately.

Examples¶

Basic Usage¶

nodetool invalidatecidrpermissionscache

After CIDR Group Changes¶

# Update CIDR group
nodetool updatecidrgroup app_servers '10.100.0.0/16,10.101.0.0/16'

# Invalidate cache to apply changes immediately
nodetool invalidatecidrpermissionscache

After Dropping a CIDR Group¶

# Remove CIDR group
nodetool dropcidrgroup deprecated_network

# Clear cache
nodetool invalidatecidrpermissionscache

Cluster-Wide Invalidation¶

# Run on all nodes for cluster-wide effect
for host in node1 node2 node3; do
    ssh "$host" "nodetool invalidatecidrpermissionscache"
done

When to Use¶

After CIDR Configuration Changes¶

# After any CIDR group modification
nodetool updatecidrgroup new_network '10.200.0.0/16'
nodetool invalidatecidrpermissionscache

Always invalidate the cache after:

Creating new CIDR groups
Updating CIDR group ranges
Dropping CIDR groups
Modifying role-to-CIDR associations

Immediate Security Response¶

# Block compromised network immediately
nodetool dropcidrgroup compromised_subnet
nodetool invalidatecidrpermissionscache

During security incidents, invalidate the cache to ensure access revocations take effect immediately.

Troubleshooting Authorization Issues¶

# Clear cache to rule out stale data
nodetool invalidatecidrpermissionscache

# Test connection from affected IP
nodetool getcidrgroupsofip 10.50.100.25

Best Practices¶

Cache Invalidation Guidelines

Run on affected nodes - Execute on all nodes where clients connect
Include in change procedures - Always invalidate after CIDR modifications
Monitor after invalidation - Watch for authorization issues after cache clear
Consider timing - Cache invalidation may briefly increase authorization latency

Non-Persistent Setting

This is a runtime operation only. The cache will automatically rebuild as new authorization checks occur. No configuration changes are persisted.

Cache Behavior

Cache entries expire based on permissions_validity setting
Invalidation clears all cached CIDR authorization decisions
New entries are cached as clients reconnect or new checks occur
High connection rates may see brief latency increase after invalidation

Performance Considerations¶

After invalidating the cache:

First authorization check for each IP requires full evaluation
Cache rebuilds automatically as checks occur
Brief increase in authorization latency is normal
Monitor cidrfilteringstats for cache performance metrics

# Check cache performance after invalidation
nodetool cidrfilteringstats

Command	Relationship
cidrfilteringstats	View cache statistics
listcidrgroups	List CIDR groups
updatecidrgroup	Modify CIDR groups
dropcidrgroup	Remove CIDR groups
reloadcidrgroupscache	Reload groups from storage
invalidatepermissionscache	Clear role permissions cache