Forum Discussion

JCmacc's avatar
JCmacc
Up to speed
2 years ago

Can't send e-mails due to IP address blacklisted due to "rDNS"

Via Outlook I can get incoming e-mails from our 2 ntlworld accounts but can not send as our IP address has just been added to a blacklist apparently. I've checked various websites and the IP address hasn't been flagged for spamming and there's no evidence of any hack or unknown sent e-mails, nor have we been sending any great number. 

One diagnostic site tells me the blacklisting is due to a change being needed by the ISP. The message is below.

 

"This IP has been flagged because it is dynamic or by suspect to be domestic use only.

If you are running an email service on this IP, ask ISP to change the rDNS

The removal of this IP from this blacklist depends on change of rDNS to match the FQDN of the mail server."

This did occur just before the Hub needed a reboot (as evidenced by an Amazon Firestick issue that was fixed by the Hub reset). One question is did the Hub error cause a DNS change that resulted in the black listing? 

 

Any advice on the issue and/or next steps would be greatly appreciated.

  • Update: Virgin Media online help sends me to Gadget Support who tell me there's no issue with Virgin Media as I can access and send e-mails from the Web based App.

    They can change settings to allow Outlook to work but it will cost me a £9.99 per month charge. This despite it's Virgin Media themselves who have blocked my IP address according to the error message I get when I try to send via Outlook.

    This can't be right.

  • 用心棒's avatar
    用心棒
    Very Insightful Person

    JCmacc wrote:

    One diagnostic site tells me the blacklisting is due to a change being needed by the ISP. The message is below.

     

    "This IP has been flagged because it is dynamic or by suspect to be domestic use only.

    If you are running an email service on this IP, ask ISP to change the rDNS


    You are using an email client (Outlook) to send via Virgin Media's email server. You are not running an email server so the above blacklisting is not relevant.

    Check that your email client is using the recommended setting as detailed here, Email settings change - Virgin Media Community - 3369438

    Should the issue persist then It would be helpful to see what, if any, error code is returned by the SMTP server when sending. From a desktop or laptop device open a Command Shell in Window or otherwise the Terminal. app and enter the following where username:password is replaced with your email address and password, i.e. richard.branson@virginmedia.com:Y54kpX5g:

    curl -v smtps://smtp.virginmedia.com -u username:password

    WARNING: Do not post the resulting output here but instead review it for possible reported causes, i.e. VM error code; choosing to ignore this warning and posting the output here unredacted or incorrectly redacted will likely reveal your email address, password and / or public IP Address.

    FYI if there is no issue then you should see the following output from the curl command:


    > AUTH PLAIN
    < 334
    > [Redacted]
    < 235 2.7.0 SMTP350 Authentication successful for user [Redacted]
    > HELP
    < 214-2.0.0 This is cmsmtp ESMTP service help
    214-2.0.0 This is cmsmtp ESMTP service help
    < 214-2.0.0 To contact postmaster send email to postmaster@virginmedia.com.
    214-2.0.0 To contact postmaster send email to postmaster@virginmedia.com.
    < 214-2.0.0 For local information send email to Postmaster at your site.
    214-2.0.0 For local information send email to Postmaster at your site.
    < 214 2.0.0 end of HELP info
    214 2.0.0 end of HELP info
    * Connection #0 to host smtp.virginmedia.com left intact

    Otherwise unsuccessful will look similar to the following; note VM error code VM320 in result:


    > AUTH PLAIN
    < 334
    > [Redacted]
    < 525 5.7.13 Authentication Denied (VM320)
    * Closing connection 0
    * TLSv1.2 (OUT), TLS alert, close notify (256):
    curl: (67) Login denied

    -- 
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    • JCmacc's avatar
      JCmacc
      Up to speed

      On the server settings - all the recommended and up to date settings are on Outlook on my Phone (as it's relatively new so recently configured). The e-mails are perfect if I use data but using wi-fi from the home Hub, the issue on e-mails being blocked when I try to send is there too.

      • David_Bn's avatar
        David_Bn
        Forum Team

        Thanks for coming back to us JCmacc.

        Interesting you mention the connection to the router appears to be the issue - with mobile data providing a positive outcome

        We can try arranging for our Internet Security team to clean your IP address to lift the issues you've been experiencing on the broadband connection.

        Check out the envelope in the top right hand corner for a private message from me

        Thanks,

        David_Bn

  • Thanks for coming back to me via private message JCmacc, and I'm pleased that this has since been resolved.

    We take the feedback offered on board and will be happy to offer future support via our Community Forums for any future service issues.

    All the best,

    David_Bn