[JAMES-774] Add documentation for the dns ttl issue

• Type: Task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.3.1, 3.0.0
• Fix Version/s: 3.0-M1
• Assignee: Danny Angus
• Reporter: Stefano Bagnara
• Created: 04/Feb/07 16:40
• Updated: 19/Oct/10 11:18
• Resolved: 11/Apr/07 12:09

Description

Add documentation to the site and/or to the config.xml about the unbounded cache issue in the JVM and how we introduced a system property networkaddress.cache.ttl that is read by phoenix at startup and used to override the java 1.4 Security.setProperty("networkaddress.cache.ttl" value.
By default in run.bat, phoenix.sh and james-server.sh (this one only in trunk) and wrapper.conf we added 300 seconds (-Dnetworkaddress.cache.ttl=300).

The cache is about positive results from dns lookups.
-1 means that the cache is never expired
0 means no cache
x>0 mean the number of seconds before expiration.

Please not that james trunk should not be affected by this cache because every usage of the InetAddress lookups have been removed by core code, but third party mailets could be afftected anyway, and this is why we added the property. James 2.3 instead still uses some InetAddress lookup and this property will save from OOM due to the unbounded cache.

Issue Links

• is related to: JAMES-592 OOM caused by unbounded cache in InetAddress (was James leaks memory slowly)
• is related to: JAMES-679 Make sure our container use an expiration for cached dns data