Website blocked by Plusnet provider

[#1]

Good afternoon,

Today I need your help, regarding our website who's not reachable from our customers using Plusnet as ISP (pro version).

They can resolve the name but can't reach the site (web page can't be reached).

They tried to ask support about this case, who told them that was related to a lack of DNSSEC but many sites don't use it so we can't be the only one blocked...

We went deeper and see that the SYN paquet comes well from our customers to our server, but they never receive our SYN ACK packet, so the TCP handshake fails. Our traceroute and other investigations show that packets are stopped at their kingston server and wouldnt go any further.

If you have the chance to try, please let me know if you can't reach the landing page: https://uk.symbility.net

Thank you for your help!

[#2]

I arrive at this url
https://uk.symbility.net/Login.aspx?ReturnUrl=%2f
I'm not using PN network, but one that also uses BT infrastructure.

[#3]

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@Gel wrote:
I arrive at this url
https://uk.symbility.net/Login.aspx?ReturnUrl=%2f

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Sadly that doesn't seem to connect via the PN network either. 

[#4]

Thank to both of you for testing.

@Gel, that confirms some customers who use BT network don't have the issue.

@MauriceC and your test confirms that is related to PN network as guessed.

The question is, what does PN to block our website (and why BTW)?

[#5 · Accepted solution]

It's due to the issue described here.

jira.innovation-hosting.com and uk.symbility.net both resolve to IP's in the same subnet.

[#6]

Hi @bobpullen, so if I well understood, this is related to a routing issue that is already under investigation PN side.

Do you have an ETA for this ticket?

Also, I saw the reference INFOPS-3100 but where could I check is followup as we aren't PN customer?

That being said, thank you very much for your help.

[#7]

Yes, it's under investigation.

I've asked for somebody to give me a nudge once some progress has been made so will pop back here once things have been sorted.

Can't provide an ETA though I'm afraid as we're dependent on third parties.

[#8]

Thank you @bobpullen, we will wait for your feedback over here.

[#9]

Should be sorted now? Let me know if not.

[#10]

Hi @bobpullen!

Our last impacted customer just told us everything is fine now, thanks for your help on that touchy case.

Have a great day.