I am using Java 1.3.1_02 servlets with Tomcat 3.2 / Apache. I would like to reset the DNS caching parameter networkaddress.cache.ttl. Where do I do this? [url removed, login to view] Explanation follows. The InetAddress class has a cache to store successful as well as unsuccessful host name resolutions. The positive caching is there to guard against DNS spoofing attacks; while the negative caching is used to improve performance. By default, the result of positive host name resolutions are cached forever, because there is no general rule to decide when it is safe to remove cache entries. The result of unsuccessful host name resolution is cached for a very short period of time (10 seconds) to improve performance. Under certain circumstances where it can be determined that DNS spoofing attacks are not possible, a Java security property can be set to a different Time-to-live (TTL) value for positive caching. Likewise, a system admin can configure a different negative caching TTL value when needed. Two Java security properties control the TTL values used for positive and negative host name resolution caching: [url removed, login to view] (default: -1) Indicates the caching policy for successful name lookups from the name service. The value is specified as as integer to indicate the number of seconds to cache the successful lookup. A value of -1 indicates "cache forever". [url removed, login to view] (default: 10) Indicates the caching policy for un-successful name lookups from the name service. The value is specified as as integer to indicate the number of seconds to cache the failure for un-successful lookups. A value of 0 indicates "never cache". A value of -1 indicates "cache forever".
Description of exactly where to change parameters in Tomcat or Java