On Saturday, 12 April 2014 12:41 PM, William Brown wrote: PS: The unreliable ISP I perceive as:
- They often return no query within an acceptable time period
- They return invalid or incorrect zone data
- They mess with TTLs or other zone data
Right.
Consider, I get home, and open my laptop. Cache is cleared, and I'm now populating that cache with the contents from the ISP.
No, why contents from ISP? Local resolver will populate cache from root servers, no?
But if you weren't to clear the cache, I could be at home caching bad records, then when I go to work they persist.
This is a glitch that when you are at home the cache still has office domain addresses cached, to which you can not connect, because you aren't connected to the office network. Do I understand it right? IMO, that's not bad cache.
You cannot have both. I would rather that cache is flushed on interface change as it prevents so many more issues than making that cache last across potential network boundaries.
Sure, no contention there. IMO, that could be a feature for NM, to clear local cache on interface change. Because NM is suitably placed to do that.
At the end of the day, I cannot stress enough, if you have an ISP with bad DNS caching or that is unreliable, you need to fault your ISP,
IMO, local resolver can help here.
--- Regards -Prasad http://feedmug.com