On 7/25/19 3:48 PM, rainer@ultra-secure.de wrote:
Am 2019-07-25 15:41, schrieb hw:
On 7/25/19 2:53 PM, rainer@ultra-secure.de wrote:
Am 2019-07-25 14:51, schrieb hw:
Hi,
how can DNS reliability, as experienced by clients on the LAN who are sending queries, be increased?
Would I have to set up some sort of cluster consisting of several servers all providing DNS services which is reachable under a single IP address known to the clients?
Just setting up several name servers and making them known to the clients for the clients to automatically switch isn't a good solution because the clients take their timeouts and users lacking even the most basic knowledge inevitably panic when the first name server does not answer queries.
Run a local cache (unbound) and enter all your local resolvers as upstreams.
That can fail just as well --- or be even worse when the clients can't switch over anymore. I have that and am avoiding to use it for some clients because it takes a while for the cache to get updated when I make changes.
However, if that cache fails, chances are that the internet connection is also down in which case it can be troublesome to even get local host names resolved. When that happens, trouble is to be expected.
Anything else is - IMHO - much more work, much more complicated
That's what I was thinking. Perhaps it is better to live with a main server and one or two slaves so the clients can keep their alternatives.
But still ... There's got to be a better way ...
and much more likely to fail, in a more spectacular way. Especially all those keepalive "solutions".
You mean like probing if the DNS server is still responsive and somehow switching over when it's not? I never tried, though it is evident that more complicated things may tend to be less reliable.
Yet it reminds me that I could actually check the name servers and dispatch a message when one fails as I'm already doing for a couple other things. That would suffice and doesn't introduce more possibilites of failure to name resolution.
I have found that I need to restart unbound if all upstreams had failed.