![]() Not bad if you have a short TTL, somewhat rubbish if you have a 1hr one. ![]() In a way, if you're looking for something about your own zone and how Google sees it, you've sort of poisoned your DNS results with Google for the TTL of your Zone. More detail - so if you've already asked for an mx record using dig -t mx and your /etc/nf is 8.8.8.8 then doing anything inside the TTL of the zone will return the cached result. But - importantly, you haven't got a cache. So, in other words, your dig client will work like a recursive DNS server would, should you ask it. Something important to note here, which I notice many people don't ever include when talking about +trace is that using +trace means the dig client will do the trace, not the DNS server specified in your config (/etc/nf). The added benefit of using +trace is that you get to see all of the separate requests made along the path. In practice since this will only query the authoritative servers rather than your local caching resolver, the result won't be stale even if those servers employ internal caching. You can, however, get dig to bypass the configured nameservers, and perform its own recursive request which goes back to the root servers. If you wanted to stop a nameserver from responding from its cache, you'd only be able to do that by altering the configuration on the nameserver, but if you don't control the nameserver, this is impossible. ![]() That's only useful when you want to directly query an authoritative nameserver. DNS does include a way to tell a server not to use recursion, but this isn't what you want. ![]() Dig itself isn't a nameserver, it is simply a tool that passes your query on to whichever nameservers you have configured, using standard DNS requests. There is no mechanism in the DNS protocol to force a nameserver to respond without using its cache. ![]()
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