If an advertiser or ad network sends you a piece of creative code (also known as an ad tag) that calls another ad server, you will need to traffic that creative as a “third-party creative.”
If you’re using DoubleClick for Publishers (DFP) or Google Ad Manager (GAM), you will be able to set this up fairly easily.
The key to successfully serving third-party creatives and minimizing reporting discrepancies is to make sure that you are properly inserting macros in the third-party code.
To add a third-party creative to your network:
1) On the Orders tab, click Creatives in the left-hand navigation.
2) Click Add creatives.
3) Begin typing to search for the advertiser whose creative you’re adding. Each creative is associated with one advertiser. Click Continue when ready.
4) Select Third-party creative.
5) Enter the name for your creative & paste the tags from a third-party ad server into the Code snippet field.
If DFP does recognize your creative, click “Insert macros” and DFP will automatically insert the appropriate macros into your code snippet.
If DFP doesn’t recognize your creative, place your cursor within the code snippet where a macro should be placed, then click the corresponding button to insert the macro.
If there are no instructions in the ad tag for where the macros should go or you’re not completely sure, it’s best to reach out to the third party directly.
For more information on inserting macros in your 3rd party creatives, check out Google’s support pages.
6) Select the target ad unit size where the creative should deliver.
Make sure that you save and accept changes and that should be it. Your third-party creative is ready to serve via your Google Ad Server.