Incoming Emails to @ntlworld.com Addresses Blocked

[robinwilson16]

Hello

I run an email server which is not blacklisted by anyone (mail.robindigital.co.uk @ [IP removed] ) yet emails sent to @ntlworld.com addresses are always blocked.

Emails to all other domains work without issue and the issue seems specific to @ntlworld.com

I have looked to see if there is a de-listing process but cannot find one.

Please can someone advise how this can be addressed.

Thanks

Robin

[Martin_N]

Hi robinwilson16,

Thank you for your post and welcome to the community. 

I'm sorry to hear about the issue with your emails. 

To confirm, do you have confirmation the ntlworld email addresses are active. 

As these are an older email type and many of them aren't active. 

^Martin

[robinwilson16]

Hello Martin

Yes the email addresses are live and in use. Emails from an Exchange Online account reach the inboxes of the users but emails from my server do not.

MX Toolbox confirms my server is not blacklisted by anyone.

Information I have read suggests NTL World addresses may default to blocking everything not whitelisted such as Exchange Online or Google Workspace so impacting anyone who runs their own email server rather than relying on blocklists and SPF records.

Is there no delisting form I can complete? If not how can I resolve this?

Thanks

Robin

[Arissa_H]

Hi Robinwilson16.

Thank you for coming back to us on this thread,

So that we can look into this a little better, please can you outline in what context are you trying to reach out to NTL addresses and why? 

Also are you a business account?

Please let us know, we here to help.

Thank you. 

[ravenstar68]

@Arissa_H My understanding is that they are not a VM user, but they are trying to send emails to ntlworld.com addresses

@robinwilson16 Are you able to post the bounce message, with email addresses redacted.  Preferably please also provide the IP address and hostname of the mail server.  I want to do some checks if I may.

Note:  I'm not a Virgin Media employee - we VIP's do have a special status though, and I run my own email server as well,  so I'm no slouch when it comes to email issues 😉 lol

Edit, If you're not happy posting the information on the main Forum, drop me a PM - (Click my name and then click send me a message).

[robinwilson16]

Thanks for the replies.

@Arissa_H: Yes that is correct. I am not a VM user but run an email server for a website who are a golf club and who communicate with users at other golf clubs, some of which use NTL addresses and all of which bounce. The problem is specific to NTL and emails to all other addresses are fine and there are no other reported issues.

@ravenstar68: Thank you. Here is a bounce message:

<REMOVED@ntlworld.com>: host mx.tb.ukmail.iss.as9143.net[212.54.56.11]
    refused to talk to me: 421 EHLO MXIN201 Your HELO/EHLO robindigital.co.uk
    is not matching your DNS configuration host-89-242-6-205.static.as13285.net
    ;id=glukpCNApcEGt;sid=glukpCNApcEGt;mta=mx6.tb;d=20230327;t=142530[CET];ipsrc=89.242.6.205;

I added the mail server above but it was removed but it is mail.robindigital.co.uk and IP is 89.242.6.205

If it gets removed again I will send it in a message.

Thanks for having a look.

Robin

[robinwilson16]

It appears blueyonder addresses also bounce but upon checking these are also with VM the same as NTL so it will be the same issue.

[robinwilson16]

Perhaps the HELO response should be mail.robindigital.co.uk?

I have now changed this so can monitor if it makes any difference.

Robin

[robinwilson16]

I think I get it now.

A reverse DNS lookup is being performed against my IP (89.242.6.205) and as my web hosting is with TalkTalk it resolves to host-89-242-6-205.static.as13285.net when my server is at mail.robindigital.co.uk

Hopefully VM does not require me to change my HELO/ELHO response to host-89-242-6-205.static.as13285.net as I think this may cause issues elsewhere then I would possibly need an SSL certificate for that address which would be hard/impossible to obtain without having authority over the parent domain (or any part of this domain).

https://mxtoolbox.com/SuperTool.aspx?action=ptr%3a89.242.6.205&run=toolpage

[ravenstar68 · Accepted solution]

You need to set the reverse DNS for your mail server to match the hostname for your server.

For example check my server mail.timothydutton.co.uk

If you do a dig for the A record:

mail.timothydutton.co.uk. 1799 IN A 51.68.196.229

Now if you do a reverse lookup on 51.68.196.229

229.196.68.51.in-addr.arpa. 86400 IN PTR mail.ravenstar68.co.uk.

Which matches the EHLO/HELO I've set for my server.

Your host should be able to advise or set the PTR record for your server IP.

Tim

@ModTeam Please leave the above information as is.