On Mon, Mar 13, 2023 at 11:14:20PM +0100, local10 wrote: > Strangely, the issue resolved itself without me having to do anything. Am > really puzzled as to what it was. Perhaps the internet provider suddenly > started to block DNS queries but then allowed them again? If so, why did > dig's message say that there was "communications error to 127.0.0.1#53: timed > out"? It really gives an impression that dig was failing to connect 127.0.0.1 > port 53, on which bind was running. > > # dig www.yahoo.com <http://www.yahoo.com> > ;; communications error to 127.0.0.1#53: timed out > ;; communications error to 127.0.0.1#53: timed out > ... > > Maybe someone will shed some light on this.
UDP doesn't have a "connection". The client sends a datagram (a one-way message) to the UDP service, and then waits to receive a reply. If the UDP service in turn sends a datagram to a third party, and waits for a reply, but never receives one... and thus never responds to the original client... then all the client knows is that it never got a response. It doesn't know why.
