Am running Debian stretch on a LAN server that also runs local authoritative DNS, DHCP, DDNS for LAN clients. I installed
cloudflared listening on a non-standard port using
--port NNN so it does not interfere with the existing DNS server. I set the DNS server to forward to
cloudflared on this port.
dig responses show it is working. After some time, sometimes minutes and sometimes hours, something goes wrong and I get many log messages such as that below, and DNS forwarding is no longer working. After some further time (hours?) the issue appears to resolve and it’s working again, at least as far as
dig requests show.
In the message below, 192.168.X.Y is the server in question. What could be the issue here?
cloudflared: time="2018-04-02T06:52:03-07:00" level=error msg="failed to connect to an HTTPS backend \"https://cloudflare-dns.com/.well-known/dns-query\"" error="failed to perform an HTTPS request: Post https://cloudflare-dns.com/.well-known/dns-query: dial tcp: lookup cloudflare-dns.com on 192.168.X.Y:53: read udp 192.168.X.Y:50592->192.168.X.Y:53: i/o timeout"