About ad blocking

Ad blocking prevents your ads from serving to inventory where you do not want them to appear. This way you can make sure your advertiser's brand does not appear in the wrong context.

You can set criteria for what counts as inventory where you ads should not appear, as follows:

  • Create a list of flagged domains where your ads should not appear.
  • Set content classifiers that indicate ads should not appear on a site if it includes the kinds of content you specify.
  • Select geographic regions outside which you don’t want your ads to be served.

Instead of sending your regular ads to sites that qualify for ad blocking, Campaign Manager sends transparent pixels or an empty VAST response.

To get started, specify your criteria for ad blocking in Verification, and then enable ad blocking in Trafficking. See the FAQ if you have questions.

Ad blocking is not supported for: click trackers, tracking ads, or impressions served to mobile in-app environments.​

How to specify ad blocking criteria

Currently, you can specify three criteria that will determine what inventory is undesirable for your ads:


  • Domains - You can choose an existing list of domains or set up a new one. Campaign Manager will check this list whenever an impression is available. Campaign Manager will prevent your ads from serving to flagged domains and will send brand-neutral ads instead. You can also create a list of allowed domains where your ads will always be served, regardless of whether they trigger content classifiers. You can include second level subdomains (like but parent and subdomains cannot exist on the same list. If your list includes subdomains, and you wish to add their parent domain, the subdomains will be deleted. If your list contains a parent domain, and you wish to add its subdomains, you must edit or delete the parent first.
  • Content classifiers - You can select content classifiers to prevent Campaign Manager from serving ads to domains that have particular kinds of content. Set these at the account, advertiser, or campaign level, depending on how widely you want these classifiers to apply.
  • Geography targeting - You can select locations (any of DMA® Region, State/Region, or Country) in which you want your impressions to serve, so that Campaign Manager will not serve ads outside these locations. Select locations at the account, advertiser, or campaign level, depending on how widely you want them to apply.

You make these choices in Verification Settings. Get started

How ad blocking works in Campaign Manager

When you enable ad blocking, here is what happens:

  1. When a request is made to Campaign Manager to serve an ad, Campaign Manager checks if the inventory matches your ad blocking criteria:

    • Is the inventory on a flagged domain (a domain where you don't want to show ads)?
    • Does it include undesirable content (content that matches a content classifier)?
    • Is it serving outside the geographic targets you’ve specified?

    (Ad blocking only affects display and in-stream placements, so Campaign Manager only checks the domain for these placement types.)

  2. If it detects any of these conditions, Campaign Manager does not send any of your standard ads—this applies to all sites, pages, and sub-domains under the domain. Instead, Campaign Manager sends invisible content (a transparent pixel or empty VAST response).

Ad blocking is enabled in Trafficking on campaigns, and can be controlled for specific sites and placements within the campaign. 

How do you choose what to send to a domain that meets your criteria for ad blocking? Your options depend on the placement type.

Display placements

For display placements that trigger blocking criteria, Campaign Manager blocks your regular ads and sends a transparent pixel instead. This is the default option. The user does not see any ad content. In fact, the user cannot even tell that a placement is there. The placement is transparent, so it looks exactly like the rest of the page. It has the same background color. Campaign Manager calls these transparent pixels brand-neutral ads.

You can assign your own creatives to brand-neutral ads. These might be creatives for a non-profit organization, or other content that is unrelated to your brand. You can assign these creatives in your advertiser properties, in the “Creative bundles” section.

Billing and reports

Whether you choose to send transparent pixels or your own brand-neutral content to display placements, Campaign Manager logs these impressions as blocked impression on your brand-neutral ads. These impressions count toward your ad serving fees.

In-stream video placements

For in-stream video placements that trigger blocking criteria, Campaign Manager blocks your regular ads and sends an empty VAST response instead. The user will not see any video content from Campaign Manager.

The empty VAST response is valid, but has no content. This ensures that the video player will not show an error. Most publishers will choose another video ad from another advertiser once they receive the empty VAST response.

(Unlike display placements, there is no option to send alternative content to the in-stream video placements on inventory with blocking criteria specified.)

Billing and reports

Campaign Manager does not log impressions for empty VAST responses, and there are no ad serving fees for these impressions.

Other placement types

Ad blocking does not prevent ads from serving to other placement types. Your regular ads will serve if the impression is eligible. Ad blocking only affects display placements serving to desktop and mobile web inventory and in-stream placements.

How ad blocking affects your campaign

  • Currently, ad blocking affects only standard ads on display placements and in-stream or VPAID creatives on in-stream video placements.

  • Ad blocking does not protect placements on mobile apps or interstitials. Ad blocking does not prevent delivery for click tracker ads or tracking ads.

  • Ad blocking does affect impression pixels that you might have assigned to track impressions on ads that are not served by Campaign Manager, if they are on display placements serving to desktop and mobile web inventory.

Pre-bid blocking

You can do pre-bid and post-impression blocking on different platforms as follows:


GDN placements do pre-bid blocking (exclusion) based on Verification settings. Note: The exception is when you have one GDN ad group that’s mapped to multiple Campaign Manager placements from different networks. In this case, GDN can’t choose which settings to use.

Display & Video 360

You can do pre-bid blocking on all classifiers in Display & Video 360, with brand safety targeting.

Campaign Manager

You can do post-impression blocking on a subset of standard classifiers in Campaign Manager.

Why ad blocking is useful

Ad blocking is useful because you may not always know which particular site your ad will end up on for each impression. One common case is when you have placements on a network rather than a specific site. Networks can include many possible sites. Some of those sites might be wrong for your ads.

Another case is when your tags pass through multiple tag management systems, including bidding platforms. If you specify ad blocking criteria ahead of time, Campaign Manager can use ad blocking to keep your ads off the wrong sites.

Ready to set up ad blocking? Start with our steps to specify blocking criteria.

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