My Email host is blocked by BT FF but not by EE 4G

[mayavirupa777]

I have been through a nightmare 5 days with no access to my Email host on my 3 computers. Luckily I can access the host via my EE mobile. And on my computers by using my phone as a Hotspot. But it has been - and still is - a huge working-from-home inconvenience.  I have done exhaustive tests via my host which establish that the BT network suddenly stopped connecting with this one specific server last Friday morning. Hub has been reset twice, configurations tested, new WAN IP. My host has specifically white-listed the address. BUT because my Broadband service is otherwise working, BT will not acknowledge a fault, assign an engineer or escalate to someone who understands complex routing issues. I have spent hours on Messaging and to Tech Support in Ireland. It basically ends up as "You have no fault" "I do have a fault" "No, you don't..." etc etc.  I have also emailed consumer-resolutions but no acknowledgement or reply. HELP!!

[licquorice]

YOU, don't have a fault, your email host does. It is up to them to raise the problem with BT via [email protected]

[mayavirupa777]

My understanding was that "Postmaster" is specifically for BT hosted email. Do you know for certain they deal with Email hosted elsewhere? 

[licquorice]

I possibly misunderstood your original post. Can you access the mail server using a different DNS server such as Google 8.8.8.8

You can't change the DNS server on the hub but you can change it on your laptop/computer.

It is still a problem for your mail host to resolve with BT if it turns out to be a DNS problem.

[mayavirupa777]

Thanks for engaging! Much appreciated. 

Thanks — yes, I did initially wonder about DNS, but we have actually ruled that out fairly conclusively.

Using the same BT connection, the hostname resolves correctly to 91.238.161.174. I also tested the IP address directly with curl, bypassing DNS altogether:

91.238.161.174:443 → Connection refused

The same test over EE 4G → TCP connection succeeds and TLS handshake completes.

More recently, from the same Ethernet-connected Mac over BT, I tested the three adjacent IPs:

91.238.161.173:443 → connects
91.238.161.174:443 → connection refused
91.238.161.175:443 → connects

So changing DNS servers wouldn't affect those tests, because the final tests are made directly against the IP addresses.

I agree that the problem needs to be resolved between BT and the mail host/network if necessary. At present Ecohosting's infrastructure team are purportedly investigating the .174 address from their side, while BT Consumer Resolutions have my complaint but haven't responded yet.

[licquorice]

Not sure why a mail server should be affected, but it could be due to web protect.

https://www.bt.com/help/security/web-threat-protect/learn-about-bt-web-protect

[mayavirupa777]

No we ruled that out on Day One. It's now Day Five so I'm sure you'll understand that I'm going quite crazy. BT & Ecohosting pointing at each other, and days pass without any progress. If you've any idea what to do next...

[licquorice]

I assume you have tried the obvious of disconnecting your line for half an hour or so in order to obtain a different public IP address.

Surely you're not the only Ecohosting customer with the problem.

[mayavirupa777]

Yes, On Day One,  and again (and again) when calling Support. It's the cure-all, except when it doesn't! And, oddly, I am apparently the only one with the issue at Ecohosting. 

[licquorice]

I'm completely out of ideas now, you've tried all the obvious solutions.

Just one other thought, have you tried accessing the server from a neighbour's/friend's BT connection?