Plusnet/BT DNS blocking .com domain

[#1]

Hi,

I’m hoping a staff member or Superuser can help escalate a domain resolution issue on the Plusnet network.

My business domain, integra-bt.com, is failing to resolve for multiple users on Plusnet connections, returning NXDOMAIN or SERVFAIL. However, it resolves perfectly via Google (8.8.8.8) and Cloudflare (1.1.1.1).

Context & Diagnostics:

• Current Status: The domain is now proxied behind Cloudflare (104.21.54.177 / 172.67.168.199).

• Previous State: The domain was briefly on a shared IP (185.158.133.1) which had a poor reputation. This has now been resolved.

• DNSSEC: I have verified via Verisign and DNSViz that there are no DNSSEC chain-of-trust issues.

• SafeGuard: This occurs even when SafeGuard is disabled on the account.

It appears the domain has been caught in a network-level "sinkhole" or stale reputation block within the BT/Plusnet DNS infrastructure.

Request: Could someone please request a refresh/flush of integra-bt.com from the BT/Plusnet security filters? We have a pre-onboarding meeting with a client tomorrow and need this resolved for Plusnet-based users.

Many thanks,

James

[#2]

Sounds URGENT!

@Gandalf, @MisterW, Anyone?

[#3]

Hi @JamesTyler 

I have flagged this with our support team, and I will let you know directly once I have a response. 

If this is something you need to discuss now, then please contact our team directly, and they will be able to help further. 

Linzi 

[#4]

Hi,

I appreciate your feedback and look forwards to hearing from you again.

I have already spoken with 1st line support, unfortunately, they couldn't find anyone to pass me through to who could assist.

Regards,

James

[#5]

Hi Team,

Any update or a direct contact for the Network Security / DNS team regarding a persistent DNS Sinkhole affecting the domain integra-bt.com?

The domain is currently being suppressed at the BT/Plusnet resolver level. This is causing a significant business impact as we have a client onboarding meeting scheduled for tomorrow.

I have performed comparative diagnostics which confirm the domain is live globally but "invisible" on the Plusnet network:

• Google DNS (8.8.8.8) / Cloudflare (1.1.1.1): Resolve correctly to our clean Cloudflare proxy IPs ($104.21.54.177$ / $172.67.168.199$).

• BT/Plusnet DNS (62.6.40.178): Returns No internal type for both IPv4 and IPv6 Addresses available (NXDOMAIN/Non-existent).

• Status: The domain has no malware (verified via VirusTotal) and has been moved to a fresh IP stack to resolve any previous shared-reputation issues.

It appears the domain is caught in a stale BT Web Protect / SafeGuard blacklist.

Could a staff member please escalate this to the DNS security desk to have the "Sinkhole" lifted, alternatively, could you provide a direct contact or ticket reference for the team that manages the Web Protect database?

We have already emailed saferbrowsing@bt.com and abuse@plus.net, but given the time-sensitive nature of our meeting tomorrow, any assistance in "poking" the relevant team would be greatly appreciated.

Many thanks,

James

[#6]

@JamesTyler - looks fine from where I'm sat 🤔

Plusnet non-Safeguard DNS: -

> nslookup integra-bt.com 212.159.6.10
Server:  cdns02.plus.net
Address:  212.159.6.10

Non-authoritative answer:
Name:    integra-bt.com
Addresses:  2606:4700:3036::6815:36b1
          2606:4700:3031::ac43:a8c7
          172.67.168.199
          104.21.54.177

Plusnet Safegaurd: -

> nslookup integra-bt.com 213.120.234.38
Server:  indnsc102.ukcore.bt.net
Address:  213.120.234.38

Non-authoritative answer:
Name:    integra-bt.com
Addresses:  2606:4700:3031::ac43:a8c7
          2606:4700:3036::6815:36b1
          104.21.54.177
          172.67.168.199

The BT IP from your post: -

> nslookup integra-bt.com 62.6.40.178
Server:  indnsc76.ukcore.bt.net
Address:  62.6.40.178

Non-authoritative answer:
Name:    integra-bt.com
Addresses:  2606:4700:3036::6815:36b1
          2606:4700:3031::ac43:a8c7
          172.67.168.199
          104.21.54.177

[#7]

@bobpullen 

I see, Static IP 80.229.24x.xx 

:~$ nslookup integra-bt.com 212.159.6.10
Server:         212.159.6.10
Address:        212.159.6.10#53

Non-authoritative answer:
*** Can't find integra-bt.com: No answer

:~$ nslookup integra-bt.com 1.1.1.1
Server:         1.1.1.1
Address:        1.1.1.1#53

Non-authoritative answer:
Name:   integra-bt.com
Address: 172.67.168.199
Name:   integra-bt.com
Address: 104.21.54.177
Name:   integra-bt.com
Address: 2606:4700:3031::ac43:a8c7
Name:   integra-bt.com
Address: 2606:4700:3036::6815:36b1

[#8]

Hi,

Thanks for looking into this for me.

This is the result of the nslookup from where I am:

"nslookup integra-bt.com 212.159.6.10
Server: cdns02.plus.net
Address: 212.159.6.10

*** No internal type for both IPv4 and IPv6 Addresses (A+AAAA) records available for integra-bt.com"

"nslookup integra-bt.com 213.120.234.38
Server: indnsc102.ukcore.bt.net
Address: 213.120.234.38

*** No internal type for both IPv4 and IPv6 Addresses (A+AAAA) records available for integra-bt.com"

"nslookup integra-bt.com 62.6.40.178
Server: indnsc76.ukcore.bt.net
Address: 62.6.40.178

*** No internal type for both IPv4 and IPv6 Addresses (A+AAAA) records available for integra-bt.com"

This obviously differs from what you're seeing. I've checked multiple devices to confirm the result hasn't been cached with the same result.

Any thoughts?

Thanks again.

James

[#9]

Another one of those weird routing issues we have encountered previously?

[#10]

So, I was checking from an EE Broadband line earlier.

From a Plusnet line (both low/high touch networks are the same), I'm not getting an answer: -

~$ dig integra-bt.com @212.159.6.10

; <<>> DiG 9.18.39-0ubuntu0.24.04.3-Ubuntu <<>> integra-bt.com @212.159.6.10
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 26584
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;integra-bt.com.            IN    A

;; Query time: 16 msec
;; SERVER: 212.159.6.10#53(212.159.6.10) (UDP)
;; WHEN: Thu Apr 23 14:49:48 BST 2026
;; MSG SIZE  rcvd: 43

~$ dig integra-bt.com @213.120.234.38

; <<>> DiG 9.18.39-0ubuntu0.24.04.3-Ubuntu <<>> integra-bt.com
@213.120.234.38
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 31905
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;integra-bt.com.            IN    A

;; Query time: 11 msec
;; SERVER: 213.120.234.38#53(213.120.234.38) (UDP)
;; WHEN: Thu Apr 23 14:50:15 BST 2026
;; MSG SIZE  rcvd: 43 

The 62.6.40.178 address times out for me on Plusnet: -

~$ dig integra-bt.com @62.6.40.178
;; communications error to 62.6.40.178#53: timed out
;; communications error to 62.6.40.178#53: timed out
;; communications error to 62.6.40.178#53: timed out

; <<>> DiG 9.18.39-0ubuntu0.24.04.3-Ubuntu <<>> integra-bt.com @62.6.40.178
;; global options: +cmd
;; no servers could be reached

And as has been observed, third party resolvers are fine: -

~$ dig integra-bt.com @1.1.1.1

; <<>> DiG 9.18.39-0ubuntu0.24.04.3-Ubuntu <<>> integra-bt.com @1.1.1.1
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 58013
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;integra-bt.com.            IN    A

;; ANSWER SECTION:
integra-bt.com.        300    IN    A    172.67.168.199
integra-bt.com.        300    IN    A    104.21.54.177

;; Query time: 24 msec
;; SERVER: 1.1.1.1#53(1.1.1.1) (UDP)
;; WHEN: Thu Apr 23 15:00:24 BST 2026
;; MSG SIZE  rcvd: 75

@JamesTyler - it's been raised with the right team but I reckon a resolution prior to tomorrow might be a tad optimisitic 😞

Edit: I retract what I said about the EE line earlier. I see the same DNS oddities on an EE line when using a machine that's isn't corporately managed. Seems something on the office network/VPN is helping things along 🤔

[#11]

Hi,

Thanks for flagging this to the correct team; I really appreciate your assistance with this.

Could you let me know if there is a way to escalate this request? As of today, the domain is still not resolving.

Best regards,

James

*Update: I've had a response from the BT Safer Browsing team. They have confirmed the site is categorised as 'Technology' and have supposedly cleared the block. However, the BT DNS servers (62.6.40.178) are still not resolving the domain. Can a moderator please check if the DNS cache for the Plusnet/BT resolvers can be manually refreshed for this domain?

[#12]

Curious. When I originally looked I had no problem seeing integra-bt.com, but now:

Hmmm… can't reach this page

Check if there is a typo in integra-bt.com.
If spelling is correct, try running Windows Network Diagnostics.

DNS_PROBE_FINISHED_NXDOMAIN

[#13]

@JamesTyler - it isn't a content control issue so whatever was done there, I don't think it will help. I checked the ticket earlier and it is being progressed, so hopefully you won't be waiting much longer.

Sorry it's taking longer than you'd like 

[#14]

It's working for me now, can you check it again please?

[#15]

...Yep. It's back again for me, also.