Subj : Re: ODD DNS behaviour on Pi ZERO W with Bullseye OS To : All From : The Natural Philosopher Date : Wed Nov 19 2025 19:39:14 On 19/11/2025 18:03, Richard Kettlewell wrote: > The Natural Philosopher writes: >> So no, I don't know what it is now using as a DNS client. >> >> Its very odd. I just did this... >> >> # dig vps.templar.co.uk >> >> ; <<>> DiG 9.16.50-Raspbian <<>> vps.templar.co.uk >> ;; global options: +cmd >> ;; Got answer: >> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 24512 >> ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1 >> >> ;; OPT PSEUDOSECTION: >> ; EDNS: version: 0, flags:; udp: 1232 >> ; COOKIE: 7f7ca1b95493f5c601000000691d9a18750f0123b174788b (good) >> ;; QUESTION SECTION: >> ;vps.templar.co.uk. IN A >> >> ;; ANSWER SECTION: >> vps.templar.co.uk. 3726 IN A 185.113.128.151 >> >> ;; Query time: 9 msec >> ;; SERVER: 192.168.0.101#53(192.168.0.101) >> ;; WHEN: Wed Nov 19 10:21:12 GMT 2025 >> ;; MSG SIZE rcvd: 90 >> ...then this... >> root@heating-controller:/var/ramlog# echo "This is more bollox isn't >> it?" | mail -a "From: oil-monitor@heating-controller" -s "another >> message" superroot@templar.co.uk >> ...and this... >> root@heating-controller:/var/ramlog# mailq >> -Queue ID- --Size-- ----Arrival Time---- -Sender/Recipient------- >> C459D1FE2E 387 Wed Nov 19 10:21:48 oil-monitor@heating-controller >> (Host or domain name not found. Name service error for >> name=vps.templar.co.uk type=MX: Host not found, try again) >> superroot@templar.co.uk >> >> -- 0 Kbytes in 1 Request. >> >> Now unless dig is using some other means than postfix to look up DNS, >> it looks like the problem is in postfix somehow. > > Maybe, but the above doesn?t prove it; you?ve asked for an A record but > Postfix asks for an MX record, so your lookup won?t have populated the > cache (if there is one). (It?ll look for the A record next, but until > it?s got the MX record it doesn?t know what A record to ask for.) > > If there is doubt about what name server is being used you could use > tcpdump to find out. > > sudo tcpdump -np -i br0 udp port 53 > > Replace br0 with your own network interface. You?ll need to check at > least loopback (lo) and any real network interfaces. > Dig...mx returns instantly with the correct answer too -- ?I know that most men, including those at ease with problems of the greatest complexity, can seldom accept even the simplest and most obvious truth if it be such as would oblige them to admit the falsity of conclusions which they have delighted in explaining to colleagues, which they have proudly taught to others, and which they have woven, thread by thread, into the fabric of their lives.? ? Leo Tolstoy --- PyGate Linux v1.5 * Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10) .