Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
Solved

DNS oddity

Posted on 2006-06-28
1
216 Views
Last Modified: 2010-03-31
Given the following code:

    ...
    InetSocketAddress isaCurrent = new InetSocketAddress("messenger.hotmail.com", 1863);
    sm_logger.info("Connecting to server '" + isaCurrent + "'.");
    ...

at the tail end of a process that had been running for upwards of a week this code resulted in the following log4j output:
   
    2006-06-21 23:34:50,797 INFO - Connecting to server 'messenger.hotmail.com/65.54.239.140:1863'.

30 seconds later after the process had been stopped and re-started the following lof4j ouput resulted:

    2006-06-21 23:35:28,250 INFO - Connecting to server 'messenger.hotmail.com/65.54.239.210:1863'.

The obvious difference between the two being that the address of 'messenger.hotmail.com' had changed to 65.54.239.210 from 65.54.239.140.  Assuming that the DNS entry had indeed been changed prior to the first log statement, I'm wondering why it took restarting the process for the address change to be recognized in my Java code?

Is it possible that the JVM caches DNS resolves and uses cached values for as long as the process runs going forward?
0
Comment
Question by:derekl
1 Comment
 
LVL 23

Accepted Solution

by:
Ajay-Singh earned 250 total points
ID: 17004447
yes, you are right. By default, JVM caches successful name lookups forever. However, you can change this by setting the following system property:

networkaddress.cache.ttl

The value -1 (by default) indicates that the lookup would be cached forerver. If this is set is 5, it would cache the successful lookup for 5 secs
0

Featured Post

Networking for the Cloud Era

Join Microsoft and Riverbed for a discussion and demonstration of enhancements to SteelConnect:
-One-click orchestration and cloud connectivity in Azure environments
-Tight integration of SD-WAN and WAN optimization capabilities
-Scalability and resiliency equal to a data center

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
javap not working 8 58
tomcat startup error 5 102
Tomcat: Unable to run tomcat service. 2 23
Why doesn't this text field show up on my Applet frame? 2 19
For beginner Java programmers or at least those new to the Eclipse IDE, the following tutorial will show some (four) ways in which you can import your Java projects to your Eclipse workbench. Introduction While learning Java can be done with…
Java functions are among the best things for programmers to work with as Java sites can be very easy to read and prepare. Java especially simplifies many processes in the coding industry as it helps integrate many forms of technology and different d…
This tutorial covers a practical example of lazy loading technique and early loading technique in a Singleton Design Pattern.
Viewers will learn how to properly install Eclipse with the necessary JDK, and will take a look at an introductory Java program. Download Eclipse installation zip file: Extract files from zip file: Download and install JDK 8: Open Eclipse and …

839 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question