DNS load balancing: UDP or TCP ?
dot at dotat.at
Tue Feb 19 16:24:45 UTC 2019
Roberto Carna <robertocarna36 at gmail.com> wrote:
> Dear, I have to balance two DNS servers for a special reason.
> The DNS clients are a mix of Windows, Cisco and Linux machines, so I
> think they ask for a FQDN using UDP and after that -if there is no
> response-, they ask the same FQDN using TCP, and so the load balancing
> will be succesful.
No, fallback to TCP relies on receiving a truncated UDP response. You
never want a DNS client to be waiting around for a response that will
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