You can use two global configuration properties to control the caching of host name-to-numeric IP address or DNS lookup results returned from the name resolution services of the underlying operating system.
To configure these properties, use the dsconfig tool.
Global configuration property Description
Sets the Java system property networkaddress.cache.ttl, and controls the length of time in seconds that a host name-to-IP address mapping can be cached. By default, it keeps resolution results for one hour (3600 seconds). This setting applies to the server and all extensions loaded by the server.
Caches host name-to-IP address results in the event of a DNS outage. By default, this is set to true, meaning name resolution results are cached. Unexpected service interruptions might occur during planned or unplanned maintenance, network outages, or an infrastructure attack. This cache can allow the server to function during a DNS outage with minimal impact. This cache is not available to server extensions.
To reduce delays due to unnecessary DNS lookups, follow these
- Maintain a connection pool in the client app rather than opening new connections for each bind.
- Add appropriate records to DNS, including PTR records.
- Add options timeout:1 or options single-request in the /etc/resolv.conf file.
- If IPv6 requests are causing issues, add -Djava.net.preferIPv4Stack=true to the start-server.java-args line in server’s config/java.properties file, so that running bin/dsjavaproperties and restarting the server no longer issues IPv6 PTR requests.