Does anyone else have trouble connecting to the forum from BT Broadband?

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jamesbarton988

Member
I have had a long standing problem going back to last December in connecting to the PC Specialist forum, though I can reach the main web site with no trouble at all.

Core site - no problem. Forum - error 404. I tried different browsers and many occasions

I'm on BT (infinity 2) at home, and I was on BT (unknown in holiday cottage) a couple of days ago when I could access it.

I contacted PCS who replied asking if I was on BT, because they have had a few complaints about members being unable to reach the forum and the only commonality is that they are on BT Internet!

Here at home I have found that my only option is using the BTWiFi connection instead (on my usual BT Home Hub 6), and that gets through to the forum immediately. If I switch back to the private WiFi connection and refresh the page it immediately jumps to 404. I tried different DNS servers, but none of them made any difference. I tried resetting the router (HomeHub). I swapped from a HH5 to a brand new HH6 (I got it free).

I posted a thread in the BT Community forum and found others who also have trouble. Strangely, not everyone does, and no one who has a third party router has trouble. In January of this year, one of those posts stated that PCS were in touch with BT to try and solve it. As of today, it isn't fixed and the only way I can type this is by connecting via BT WiFi.

Today I spoke with BT, following up on my complaint to them from earlier in the year, and basically they think it might be the protection included in the Home Hub, which blocks this site as being risky! But there seems to be no way to find out or fix it, unless I am prepared to pay for a BT Engineer to investigate! They claim I am the only one to complain and are taking it no further.

Is PCS in contact with BT? Am I indeed the only one who is affected that cares?
 
T

Tony1044

Prolific Poster
I used to see the same thing when I accessed via EE on my mobile.

It was eventually resolved but in the meantime, as Oussebon says, use say Google DNS and/or Quad9 on 8.8.8.8 and 9.9.9.9

BT used to have a nasty habit on their transparent proxy of routing all DNS traffic through their own servers regardless of whether you set others up or not...I believe they have stopped that nasty practice now though.
 
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Tony1044

Prolific Poster
I didn't know they had a free - let alone free and secure - offering. Thank you for that.

My gateway now points to 1.1.1.1, 9.9.9.9 and 8.8.8.8 as the preferred order :)

sophos dns1.png
 
R

ricclo

Member
I don't understand this at all. I'm on BT Infinity, and for a long time I believed that the PC Specialist website was just broken. Then I got to wondering how Google searches were still getting recent hits on this forum, and I found this thread. I connected via my phone's hotspot instead, and all was good.

However!

- If it's to do with DNS, how come the 404 page is from the PC Specialist site?
- It's an HTTPS connection, BT shouldn't be able to see the URL at all, just the IP address and the hostname via SNI.
- When I use Chrome on BT Infinity, I get a 404, but the forums work in Firefox.

Hmm. Maybe there's some strange under the hood Ajax stuff going on, involving a different IP address which BT Infinity does block? I shall investigate.
 
T

Tony1044

Prolific Poster
I used to have issues connecting the forums - and only the forums - from my mobile phone on EE. This was a long time before BT bought them, so no obvious links.

I did report it but got the impression it was falling on deaf ears as it went unfixed for a very long time.

It then just sprang into life one day.

I also pointed out the same thing - it cannot be DNS issues because /forums is simply another directory under www.pcspecialist.co.uk and the 404 is generated by the web software run by PCS.

I came to the same conclusion that it was some kind of weird geoblock going wrong - I've occasionally had other sites randomly tell me I cannot access them from the location I am currently in and then sort themselves out again.

In terms of BT not seeing into the traffic - don't bet. They used to use a transparent proxy, including a man in the middle (MITM) certificate and appliance. Though it's worth noting that I understand they stopped this practice some time ago, it meant that no matter what DNS servers you used, your DNS queries ultimately always went via BT and the MITM approach meant they could decrypt any SSL traffic.

It's very common in the workplace- you can tell if you look at the certificate of a secure site. I am connected at work and look what the certificate says is for https://www.pcspecialist.co.uk:

MITM Cert.png

It's naughty and it's difficult to do outside of a corporate organisation without notice nowadays. It can also break if you're setup to use certificate pinning, but that isn't normally adopted much.

The main difference here is the proxy server isn't transparent so I can see easily there's something in the middle. Not so much when the proxy is transparent.
 
ubuysa

ubuysa

The BSOD Doctor
It might well be a vBulletin issue. These fora still use vBulletin 4 and there was some talk last year about how best to upgrade the fora....
 
R

ricclo

Member
I think I've found a clue.

Here's a successful wget via my phone hotspot:

richard@lucente:~/tmp$ wget https://www.pcspecialist.co.uk/forums/
--2019-01-24 14:55:14-- https://www.pcspecialist.co.uk/forums/
Resolving www.pcspecialist.co.uk (www.pcspecialist.co.uk)... 104.20.7.72, 104.20.6.72, 2606:4700:10::6814:648, ...
Connecting to www.pcspecialist.co.uk (www.pcspecialist.co.uk)|104.20.7.72|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [text/html]
Saving to: ‘index.html.1’

And here's a failed one via BT Infinity:

richard@lucente:~/tmp$ wget https://www.pcspecialist.co.uk/forums/
--2019-01-24 14:56:39-- https://www.pcspecialist.co.uk/forums/
Resolving www.pcspecialist.co.uk (www.pcspecialist.co.uk)... 2606:4700:10::6814:648, 2606:4700:10::6814:748, 104.20.7.72, ...
Connecting to www.pcspecialist.co.uk (www.pcspecialist.co.uk)|2606:4700:10::6814:648|:443... connected.
HTTP request sent, awaiting response... 302 Found
Location: /404/ [following]
--2019-01-24 14:56:39-- https://www.pcspecialist.co.uk/404/
Reusing existing connection to [www.pcspecialist.co.uk]:443.
HTTP request sent, awaiting response... 404 Not Found
2019-01-24 14:56:40 ERROR 404: Not Found.


Note that the BT Infinity fetch uses the IPv6 address, most probably because the DNS server put it first.
 
SpyderTracks

SpyderTracks

We love you Ukraine
@ricclo that would probably explain it then if the bt dns is listing an IPV6 address that won’t resolve.

Wasn’t aware of that command, very handy!
 
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Tony1044

Prolific Poster
No wget natively in Windows.

Hmm. That suggests to me that, given it's a 404 error it's not DNS but rather PCS haven't associated any IPv6 bindings to the forum.
 
R

ricclo

Member
If I'm correct that the /forum URI fails when the browser connection is by IPv6, then it must be a misconfiguration somewhere between the main pcspecialist site and the server running the PHP forum software (which is probably using fastcgi). If there's a reverse proxy such as NGINX in front of the forum server, it might be as simple as missing out the bit of config that specifies the IPv6 listening port.
 
R

ricclo

Member
Yup, it definitely happens with IPv6. I temporarily disable IPv6:

sudo sysctl -w net.ipv6.conf.default.disable_ipv6=1 ; sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1

And the forums are working again.
 
SpyderTracks

SpyderTracks

We love you Ukraine
ricclo said:
Yup, it definitely happens with IPv6. I temporarily disable IPv6:

sudo sysctl -w net.ipv6.conf.default.disable_ipv6=1 ; sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1

And the forums are working again.
Click to expand...

Tony1044 said:
Nice work. So they need to bind IPv6 to the forums.
Click to expand...

If it's ok with you guys, I'll contact the Admins and point them to this thread, would be highly beneficial to get IPV6 enabled for any BT customers!
 
T

Tony1044

Prolific Poster
SpyderTracks said:
If it's ok with you guys, I'll contact the Admins and point them to this thread, would be highly beneficial to get IPV6 enabled for any BT customers!
Click to expand...

Yes mate - I wonder what changed with my EE mobile to presumably swap back to IPv4 when it sprang back into life.
 
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