rithvikp1998 opened a new issue, #6238: URL: https://github.com/apache/jmeter/issues/6238
### Expected behavior I have observed two different problems with DNS Cache Manager: 1. DNS Cache Manager takes a list of DNS servers and round-robins through them for every lookup. However, for any given lookup, if the DNS server returns a failure, cache manager fails the request instead of checking the next server. This is problematic while trying to use a list of zoned authoritative servers as every server may not have all the records. This is in contrast to behavior of say `/etc/resolv.conf` in Linux which checks the next server in the list until it finds a match. I checked the code and this is happening because DNS cache manager is using dnsjava's `ExtendedResolver` under the hood which only tries a different server if there is an `IOException` while making request to the current server. Even if the current server refuses the request without throwing an exception, `ExtendedResolver` returns an empty result without trying a different server. 2. DNS Cache Manager has a setting to Clear Cache After Each Iteration. When enabled, it clears the JMeter thread-local cache before starting the next iteration. However, it doesn't clear the DNS resolver's cache so the result could still be coming from a cache. To test this, I created a simple test with 10 iterations of a http request and enabled the clear cache setting and captured the DNS requests using Wireshark. The expectation is that there'd be 10 calls to DNS, however there is only 1 call to DNS and remaining 9 requests are using the cached value. ### Actual behavior _No response_ ### Steps to reproduce the problem Any JMeter test with a DNS cache manager would reproduce the issue. ### JMeter Version 5.5 ### Java Version 8 ### OS Version Windows 11 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: dev-unsubscr...@jmeter.apache.org.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
