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How can I set up reverse DNS on my domain name?

Note: You should only attempt to do this if you have experience in setting up mail servers.

If you are running your own local mail server you may encounter problems sending emails through some spam filtering systems because of security processes known as reverse DNS lookup (rDNS).

To prevent email from being 'returned to sender' you need to make sure that the IP address you use with your mail server is correctly associated with your domain name.

BT can provide custom rDNS setup at no additional cost. Please use our reverse DNS form .

When you fill out the form you'll need:

  • the BT Business Broadband Static IP address you wish to use for RDNS (usually mail server IP) and send your forward record, for example 213.x.x.x > mail.mydomain.com.

We will check that the owner of the domain is also the BT Business Broadband account holder and that the static IP matches that assigned to the Broadband account.

If you are requesting rDNS to be set up for more than eight IPs you must provide technical justification for each rDNS entry.

Requests are processed manually and usually completed within seven days, however, delays may occur during periods of heavy demand.

After processing, an email is sent to your primary user account to confirm the setup of your rDNS.

Please note the following:

  • A maximum of eight IP addresses can be delegated.
  • BT does not delegate authority for rDNS entries.
  • No more than one rDNS record is possible per IP address.
  • rDNS entries are set up at the discretion of BT.

To find out how to change or remove your existing custom rDNS settings, see
How can I change or remove the reverse DNS I set up on my domain name?

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