How to correctly create waterfall using DFP


I’m trying to figure out something about system behavior. So, let’s say I set up Sovrn with the DFP passback codes. What happens when -

Sovrn has no ads to display so it uses the passback tag essentially displays DFP tags in the window. How does DFP know not to send the impression to Sovrn again? I’m going to use the built-in Adsense option in DFP, to capture unfilled impressions if that matters.

I wonder how DFP knows when it’s being called from the my site itself and when it’s being called from within a Sovrn (the passback tags there). Are the tags different? Obviously, I don’t want to create a loop.

Thanks in advance for any calrifications!


I’m setting ads up in DFP now and I see that for each ad unit I can generate two different tag. The GPT and the passback tag. So I need to place the first in my site’s template and the second in the Sovrn passback tag area?


Hi @Anne

These are great questions!

The passback technology is written within the script of the ad units themselves. Unless you have multiple sovrn tags implemented within the same zone’s waterfall setup, the request will not return to sovrn demand for bidding. Because Google AdSense is a 100% fill solution, we highly recommend placing them at the bottom of your stack to ensure that every request is filled. This allows you to target higher CPM’s with your sovrn tags, and other partners, to increase your overall yield and build out your waterfall.

The call or request is essentially a command that triggers DFP to filter through partners based on their set priority. The command is completed once a bid is won or each partner passes on the request. It will not loop through the partners again.

Below I have copied two resources from our Learn Hub outlining how to properly install and traffic all tags within DFP. Each publisher set up is different so please feel free to take a look and continue to reach out with any further questions!


I’ve personally never bothered with the DFP passbacks.

I much prefer to use the “Daisy Chain” method, where you just chain networks together to build out your waterfall. In theory its probably “better” in some fashion to do this within DFP (and you could argue that its senseless and should just invest time in Header Bidding) but it certainly does work to use a Daisy Chain.

Here you trigger the first network in your chain (Could be Sovrn) and then each network passes to the next when they don’t fill the impression. You might have Sovrn-OpenX-Rubicon-Adsense - putting AdSense at the end ensures you fill everything.

By no means is a Daisy chain the best way to target ads, but its a technique which has certainly worked since the beginning. I’ve always found the daisy chain easier to wrap my head around, and even when we’ve moved to header bidding for most sites there’s always a few impressions at the bottom we “mop up” with a small chain.