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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 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 setion of the Twilio SendGrid App.

For more about Reverse DNS, see "How to set up reverse DNS" in the Twilio SendGrid documentation.

Retrieve all reverse DNS records

GET /whitelabel/ips

This endpoint allows you to retrieve all of the Reverse DNS records created by this account.

You may include a search key by using the ip query string parameter. This enables you to perform a prefix search for a given IP segment (e.g., ?ip="192.").

Use the limit query string parameter to reduce the number of records returned. All records will be returned if you have fewer records than the specified limit.

The offset query string parameter allows you to specify a non-zero index from which records will be returned. For example, if you have ten records, ?offset=5 will return the last five records (at indexes 5 through 9). The list starts at index zero.

Authentication

  • API Key

Headers

Authorization
string
default: Bearer <<YOUR_API_KEY_HERE>>
required
on-behalf-of
string
default: The subuser's username. This header generates the API call as if the subuser account was making the call.

Query String

limit
integer

The number of results to return.

default: None
offset
integer

The point in the list to begin retrieving results.

default: None
ip
string

The IP address segment that you'd like to use in a prefix search.

default: None

Responses

array[object]
id
integer

The ID of the Reverse DNS.

ip
string

The IP address that this Reverse DNS was created for.

rdns
string

The reverse DNS record for the IP address. This points to the Reverse DNS subdomain.

users
array[object]

The users who are able to send mail from the IP address.

username
string

The username of a user who can send mail from the IP address.

user_id
integer

The ID of a user who can send mail from the IP address.

subdomain
string

The subdomain created for this reverse DNS. This is where the rDNS record points.

domain
string

The root, or sending, domain.

valid
boolean

Indicates if this is a valid Reverse DNS.

legacy
boolean

Indicates if this Reverse DNS was created using the legacy whitelabel tool. If it is a legacy whitelabel, it will still function, but you'll need to create a new Reverse DNS if you need to update it.

last_validation_attempt_at
integer

A Unix epoch timestamp representing the last time of a validation attempt.

a_record
object
valid
boolean

Indicates if the a_record is valid.

required
type
string

The type of DNS record.

required
host
string

This is the web address that will be mapped to the IP address.

required
data
string

The IP address being set up with Reverse DNS.

required
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