Internet Tip: DNS caching can make DNS changes erratic…

Fred Stluka
1 min readJun 11, 2021


Internet Tips fans,

This is part 2 of the 15th tip in a series of tips on how to do tricky things with URLs.

Warning: DNS caching can also cause erratic behavior (not only the delays I explained in a previous tip) when you change a DNS record. I’m not sure exactly why, but I’m seeing a case today (right now) where the IP address reported by nslookup keeps switching back and forth between old and new values. Not good…


BTW, this is NOT the “whole lot more interesting” 19th tip that I promised yesterday, about phishers. That one got bumped by this problem I saw today. This is really part 2 of the 15th tip I sent out May 27. The “whole lot more interesting” 19th tip is coming soon [said Fermat :-]…

(If you’ve been to the page recently, be sure to refresh your browser to see the latest version, dated 6/11/2021.)

— Fred