# Reverse DNS

Reverse DNS (formerly IP Whitelabel) allows mailbox providers to verify the sender of an email by performing a reverse DNS lookup upon receipt of the emails you send.

Reverse DNS is available for [dedicated IP addresses](/docs/sendgrid/ui/account-and-settings/dedicated-ip-addresses/) only.

When setting up reverse DNS, Twilio SendGrid will provide an A Record (address record) for you to add to your DNS records. The A Record maps your sending domain to a dedicated Twilio SendGrid IP address.

A Reverse DNS consists of a subdomain and domain that will be used to generate a reverse DNS record for a given IP address. Once Twilio SendGrid has verified that the appropriate A record for the IP address has been created, the appropriate reverse DNS record for the IP address is generated.

You can also manage your reverse DNS settings in the [Sender Authentication section of the Twilio SendGrid App](https://app.sendgrid.com/settings/sender_auth).

For more about Reverse DNS, see ["How to set up reverse DNS"](/docs/sendgrid/ui/account-and-settings/how-to-set-up-reverse-dns/) in the Twilio SendGrid documentation.