Connection timed out with smtp.ntlworld.com

[Rawcous]

Hello,

I have been running my small domestic private domain servers for over 10 years now. I suddenly realised today that I am currently unable to send emails via smtp.ntlworld.com from my home location. In fact it seems that this has been the case for a few weeks now. I can however receive emails for my domain without any problems. When trying to send emails I receieve the message "Connection timed out with smtp.ntlworld.com"

I had issues last year with sending emails with DKIM / DMARC authentication which a couple of guys on this forum thankfully proved to be an issue with the Virgin Media settings on my account.

Any ideas / any more information needed from me?

Regards,

Rawcous

[Rawcous]

Cheers for your help to-date Tim,

As you stated I do have a dynamic address rather than static but my solution to this is:

1. I moved my domain from the original vendor I purchased it from to a DNS host

2. My new DNS host allows me to run a script locally on my domain servers that every X mins check my WAN address and then compare them to my domain account DNS details. If they are different then they are updated to match the WAN.

3. To test the above I amended my router's default MAC address which eventually resulted in my WAN address changing - left it a couple of minutes until my script kicked in and hey presto it updated my DNS entries

It works like magic.

Regards.

[Rawcous]

Evening all,

This is the part I really hate the most - you know the part where you have to hold your hands up and admit your findings...

After doing alot of investigations my side I have finally discovered and fixed the root cause. I use a combination of Linux iptables firewall rules and geoip updates to block connections to and from countries of my choosing - well it seems adding the Netherlands (who are pretty much the home of domain registrars etc) to the list (as a result of a no. of  suspicious connection attempts to my servers) of countries to block is not a good idea and results in connection timeouts.

I thought I would confess my sins just in case anyonbe has decided to invest any time on this.

Thanks anyway guys!

Regards.

[Molly_G]

Hey @Rawcous,

Thanks for your recent posts and sorry to hear of the time out issue you were having!

Really appreciate you dropping back with your findings - glad you've been able to resolve this.

Kind regards,

[ravenstar68 · Accepted solution]

@Rawcous 

It looks as if VM have modified where the IMAP/POP3 SMTP gateways are.

C:\Users\timdu>dig smtp.virginmedia.com

; <<>> DiG 9.16.16 <<>> smtp.virginmedia.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 52303
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;smtp.virginmedia.com. IN A

;; ANSWER SECTION:
smtp.virginmedia.com. 300 IN CNAME mail-virginmedia-com.tb.ukmail.iss.as9143.net.
mail-virginmedia-com.tb.ukmail.iss.as9143.net. 916 IN A 212.54.56.51

;; Query time: 32 msec
;; SERVER: 192.168.1.254#53(192.168.1.254)
;; WHEN: Thu Jul 01 20:17:23 GMT Summer Time 2021
;; MSG SIZE rcvd: 124

It looks as if they've taken the old Knowsley servers out of the system and have the whole lot based in the Netherlands now.

That would be why your changes blocked them out..

Tim

[Rawcous]

@Ravenstar68

It seems great minds think alike re:VM and NL. Just also performed the dig command on smtp.ntlworld.com and the IP is part of the same address range 212.54.56.52 rather than .51 (for .virginmedia.com) based out of good 'ole NL.

Simple solution for me is to simply block any suspicious activity from the NL on an individual IP basis

I still appreciate your suggestion of the Cloud mail server solution - maybe something for me to consider for future projects as I may be purchasing another domain shortly

Regards.