General Actions:
A default banner is a banner that is displayed when the system cannot use any appropriate plan, e.g. when a plan reaches it´s limits, targeting or eCPM requirement are not fulfilled, etc.
You can use self-promo banner type, displaying code of third party (e.g. google ... )
We do recommend to insert .img banner type. By this method, you may use all available impressions.
There is no available statistics for default banners.
In case you haven´t defined a default banner or a campaign of low priority without targeting with .img banner type, fallback will be displayed in cases written above.
How to set default banner in adserver
How to set default banner in SSP