Comment by buzer
7 years ago
> An extreme example that lasted almost six months was a web spider that just refused to update their DNS records and continued to request websites using the old addresses.
It may have been Java client that was not restarted. At least for older versions of Java the default was to cache result forever.
Yep, older java versions had some ridiculous caching of both positive and negative DNS responses. That was some weird problem to troubleshoot. We ended up writing our own caching then, back in Java7ish. And the first version of our DNS caching was broken and promptly triggered load alerts on 2 DNS servers of our operations team by issuing ... a lot of DNS queries very very quickly :)