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From Nick Johnson <>
Subject commons-daemon and InetAddress DNS caching
Date Sun, 28 Oct 2007 20:35:32 GMT
Does commons-daemon/jsvc do anything special or different for hostname 
resolution than running a plain JVM would?  Or to ask the question another 
way, is it possible that parameters configured in would be 
ignored because the JVM was started from jsvc instead of java?

I ask because when running Tomcat from jsvc, no matter what I try to do to 
stop negative caching (configuring or using the deprecated 
Sun-specific properties), hostnames are getting positive and 
negative cached forever.  I can verify that the JVM does not attempt a 
second lookup by watching traffic on port 53 with tcpdump.

If I write a small test program to perform a lookup for a host for which 
I've firewalled its DNS server, then wait for me to remove the entry for 
the firewall, then perform the lookup again, this works as-expected... the 
address is not cached forever.

But in my code to validate URLs submitted by users, once a hostname has 
failed once, it always fails, with no further attempts at lookups.  
Restarting Tomcat/jsvc will always clear the problem. (Because by then the 
host has finally resolvedand will be present in the nameserver's cache.)



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