How do cookies affect frequency capping?

The frequency capping option will limit the exposure of a campaign/ banner. This is achieved through the use of cookies. Browsers distinguish between first party cookies and third party cookies.

-       First party cookies are those whose domain is the same as the domain of the visited website. For example, a cookie whose domain is placed by

-       Third party cookies are cookies whose domain is different from the visited website. For example, a cookie whose domain is placed on

Users can edit their browser preferences to accept/not accept these different cookie types. However, some browsers do not accept third party cookies by default. If your ad server is using a Switch domain (e.g then the cookies for frequency capping will be third party cookies.

In cases where first and/or third party cookies are not accepted, campaigns and banners that have frequency caps applied will only deliver if the “deliver to cookieless users” is applied.

More commonly third party cookies are not accepted than first party, such is the case with some mobile browsers. To overcome this issue you should talk to your account manager or the support team about setting up a CNAME record for your Switch ad server. A CNAME record is a type of resource record in the Domain Name System (DNS) used to specify that a domain name is an alias for another domain. Basically, this would allow for a  sub domain to be set up that points to your Switch ad server. The use of this would essentially mask the Switch domain allowing a cookie to be set from a first party domain rather than a third party domain.