On 3/31/21 10:00 AM, Tony Finch wrote:
Because of this, if it's important for you to avoid multi-second DNS lookup times ... you need to design your system so that the libc resolver never tries to talk to a DNS server that isn't available.
I've seen various client OSs fail in really weird ways when the first DNS server in the list doesn't respond quick enough, much less never.
Another way is a high availability setup for your recursive servers.
+1 to something like VRRP / CARP / routing tricks to make sure that the Virtual / Service IP that client's use as the first DNS server is always available. Even if the first and second IP are on the same system for a few minutes while the other is patched.
-- Grant. . . . unix || die
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