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groupboard
Aspiring Contributor
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Message 1 of 2

BT DNS servers breaking for some sites

It looks like www.groupworld.net can't be accessed from BT. The problem seems to happen every 6 months. You can see from the trace commands below that it is an issue with BT's DNS servers (because dig +trace works, but a regular dig fails). Any idea why this keeps happening? There is no problem with the domain itself, and the two other domains hosted on the same server are both resolving okay.

dig @81.138.206.228 groupworld.net

; <<>> DiG 9.6.1-P3 <<>> @81.138.206.228 groupworld.net
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 25947
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;groupworld.net. IN A

;; Query time: 290 msec
;; SERVER: 81.138.206.228#53(81.138.206.228)
;; WHEN: Wed Dec 12 12:24:19 2018
;; MSG SIZE rcvd: 32

dig @81.138.206.228 groupworld.net +trace

; <<>> DiG 9.6.1-P3 <<>> @81.138.206.228 groupworld.net +trace
; (1 server found)
;; global options: +cmd
. 600 IN NS e.root-servers.net.
. 600 IN NS f.root-servers.net.
. 600 IN NS g.root-servers.net.
. 600 IN NS h.root-servers.net.
. 600 IN NS i.root-servers.net.
. 600 IN NS j.root-servers.net.
. 600 IN NS k.root-servers.net.
. 600 IN NS l.root-servers.net.
. 600 IN NS a.root-servers.net.
. 600 IN NS m.root-servers.net.
. 600 IN NS b.root-servers.net.
. 600 IN NS c.root-servers.net.
. 600 IN NS d.root-servers.net.
;; Received 508 bytes from 81.138.206.228#53(81.138.206.228) in 243 ms

net. 172800 IN NS a.gtld-servers.net.
net. 172800 IN NS b.gtld-servers.net.
net. 172800 IN NS c.gtld-servers.net.
net. 172800 IN NS d.gtld-servers.net.
net. 172800 IN NS e.gtld-servers.net.
net. 172800 IN NS f.gtld-servers.net.
net. 172800 IN NS g.gtld-servers.net.
net. 172800 IN NS h.gtld-servers.net.
net. 172800 IN NS i.gtld-servers.net.
net. 172800 IN NS j.gtld-servers.net.
net. 172800 IN NS k.gtld-servers.net.
net. 172800 IN NS l.gtld-servers.net.
net. 172800 IN NS m.gtld-servers.net.
;; Received 489 bytes from 199.7.91.13#53(d.root-servers.net) in 16 ms

groupworld.net. 172800 IN NS ns09.domaincontrol.com.
groupworld.net. 172800 IN NS ns10.domaincontrol.com.
;; Received 175 bytes from 192.26.92.30#53(c.gtld-servers.net) in 85 ms

groupworld.net. 3600 IN A 167.114.119.109
groupworld.net. 3600 IN NS ns09.domaincontrol.com.
groupworld.net. 3600 IN NS ns10.domaincontrol.com.
;; Received 103 bytes from 173.201.72.5#53(ns10.domaincontrol.com) in 14 ms

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groupboard
Aspiring Contributor
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Message 2 of 2

Re: BT DNS servers breaking for some sites

After 3 days of investigation (with no help at all from BT), I discovered the problem is that BT is relying on a blacklist that says "FALSE POSITIVE RISK: High" (it's actually close to 100% false positive, based on our investigation).  There are about 1000, legitimate sites added to this blacklist each day, with names including common words like "dream", "build", "group", "world", "yard", "which", "under", etc. Some legitimate sites currently on this list which are blocked by BT include:
*Edited by Mod*

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