It is a JVM setting. You do not need to change IS settings.
Modify server.bat/server.sh to add the command-line properties (the properties starting with sun.net). Or modify the java.security file located in %JRE%\lib\security of the JVM you’re using to run IS (the networkaddress properties).
I would suggest setting the TTL to 0 so that the JVM never caches. You’ll also want to set negative.ttl to 0 to never cache failed lookups.
#Integration-Server-and-ESB#webmethods-Protocol-and-Transport#webMethods