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dns-cache

Syntax

Hierarchy Level

Description

Define security policy DNS cache behaviors.

When you don’t configure this statement [edit security policies dns-cache]:

  • If all DNS servers time out, the system removes the IP address from the cache.
  • If none of the DNS servers return a valid IP and the last one times out, the IP address is removed from the cache.

When you configure the edit security policies dns-cache error-response-delete-ip retry-interval seconds, the system waits for the specified interval before resending DNS requests after deleting the IP address from the cache.

Previously (prior to Junos OS Release 23.1R1), if a DNS server returned an error, the IP address was removed from the cache (only with error-response-delete-ip enabled). Timeouts were treated differently and didn’t affect the cache. A valid response updated the cache, and on cache expiry, the system retried DNS resolution—updating the cache if any server responded with a valid IP.

Options

error-response-delete-ip

Clear DNS cache entry IP on error DNS response

  • Values:

    retry-interval

    Interval between deleting IP and resending DNS requests

    • Range: 5 through 86400 seconds.

    • Default: 300 seconds.

Required Privilege Level

security

Release Information

Statement introduced in Junos OS Release 20.1R1.