13-6 CHAPTER 13: DNS C OMMANDSSet Commands This section describes the following DNS Set commands: set dns set dns server preference name addressset dns Sets the global parameters for DNS; both local DNS hosts (list dns hosts) andremote DNS servers (list dns servers), and DNS caching and negative cachingparameters, in support of DNS host rotation for load balancing.The following parameters are associated with this command:cache [enabled | disabled | clear]cache_maxttl <0 - 2147483>domain_name intercept_requestncache [enabled | disabled | clear]ncache_maxttl <0 - 2147483>number_retries timeout These parameters are described in the following table.Parameters Descriptioncache Enables or disables DNS caching. Setting to CLEAR flushes the DNS cache.The default is disabled.cache_maxttl Maximum time in seconds DNS cache entries remain in the DNS cachebefore they’re flushed. The range is 0 - 2147483.domain_name Default domain designation to be used if no domain is specified (by adddns server command) in the name to be resolved. For example: usr.com.The limit is 64 ASCII characters.intercept_requestncache Enables or disables negative DNS caching. Setting to CLEAR flushes theDNS negative cache. The negative DNS cache contains entries the DNSserver found to be in error. For example, if the host name abc.xyz.comdoesn’t exist, the DNS server will return a non-existent name error.ncache_maxttl Maximum time in seconds DNS negative cache entries remain in the DNSnegative cache before they’re flushed. The range is 0 - 2147483.number_retries Number of times the resolve name request will be sent to each NameServer if the server fails to respond to a request before the timeout period.The default is 1. The range is 1-5.timeout Interval in seconds to wait before deciding a request to a Name Server hastimed out. Minimum interval and default is 5 seconds, maximum intervalis 245 seconds.
