BT DNS not resolving certain addresses - e.g. www.aerobus.fr

[bobpullen]

@durks - can you get to bt.com?

I recall an odd occasion some time ago where BT's nameservers seemed to be refusing all connection attempts from my IP address. I resolved the issue by downing my router for a period of time so I was assigned a new WAN IP address.

FWIW, the domain name resolves fine for me: -

~$ dig www.aerobus.fr @81.139.56.100

; <<>> DiG 9.18.49-1~deb12u1-Debian <<>> www.aerobus.fr @81.139.56.100
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 1476
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;www.aerobus.fr.                        IN      A

;; ANSWER SECTION:
www.aerobus.fr.         60      IN      CNAME   book.distribusion.com.
book.distribusion.com.  60      IN      A       34.160.19.16

;; Query time: 104 msec
;; SERVER: 81.139.56.100#53(81.139.56.100) (UDP)
;; WHEN: Fri May 22 21:09:10 BST 2026
;; MSG SIZE  rcvd: 94

[durks]

Thanks for the reply.

And yes - I can definitely get to bt.com.

By now, I am quite certain that the problem I am described is being caused by an IP routing error far downstream from me. But the exact cause is impossible for me to diagnose - and I don't really know to whom I should escalate. I am pretty sure that the problem will be noticed fixed - in due course!

[bobpullen]

@durks - if the problem is routing to the domain's nameservers then am I correct to assume that using a non-BT DNS server has no bearing on things, i.e. that fails too?

I still maintain that it's worth you powering things off for a while so you're reassigned a new public IP to see if that helps.

If it's of any help, this is my route to the domain's nameservers over IPv6 and IPv4 (and as mentioned, I have no issues resolving the domain): -

> tracert ns-219.awsdns-27.com

Tracing route to ns-219.awsdns-27.com [2600:9000:5300:db00::1]
over a maximum of 30 hops:

  1    <1 ms    <1 ms    <1 ms  2a00:23c6:d00b:8c01::1
  2     1 ms     1 ms     1 ms  2a00:2302::1103:203:3c3
  3     *        *        *     Request timed out.
  4     *        8 ms     *     2a00:2302::1102:100:49
  5     8 ms     8 ms     7 ms  2a00:2380:14::221
  6     8 ms     8 ms     8 ms  core5-hu0-3-0-26.faraday.ukcore.bt.net [2a00:2380:c::338]
  7     9 ms     9 ms     9 ms  2a00:2000:2066::7c
  8    14 ms    14 ms    14 ms  t2c3-et-5-1-5.nl-ams2.gia.bt.net [2a00:2000:0:80c0::5a]
  9     *        *        *     Request timed out.
 10     *        *        *     Request timed out.
 11     *        *        *     Request timed out.
 12     *        *        *     Request timed out.
 13     *        *        *     Request timed out.
 14    16 ms    16 ms    16 ms  ns-219.awsdns-27.com [2600:9000:5300:db00::1]

> tracert -4 ns-219.awsdns-27.com

Tracing route to ns-219.awsdns-27.com [205.251.192.219]
over a maximum of 30 hops:

  1    <1 ms    <1 ms    <1 ms  hub.home.arpa [192.168.1.254]
  2     1 ms     1 ms     1 ms  172.16.17.177
  3     *        *        *     Request timed out.
  4     8 ms     8 ms     8 ms  109.159.255.96
  5     8 ms     8 ms     8 ms  109.159.250.147
  6    10 ms    10 ms    10 ms  core5-hu0-0-0-26.faraday.ukcore.bt.net [195.99.127.68]
  7     7 ms     7 ms     8 ms  166-49-209-132.gia.bt.net [166.49.209.132]
  8    14 ms    14 ms    15 ms  t2c3-et-5-1-2.nl-ams2.gia.bt.net [166.49.208.217]
  9     *        *        *     Request timed out.
 10     *        *        *     Request timed out.
 11     *        *        *     Request timed out.
 12     *        *        *     Request timed out.
 13     *        *        *     Request timed out.
 14    15 ms    15 ms    15 ms  ns-219.awsdns-27.com [205.251.192.219]