SuppressionList is most often used with LeadConduit Classic for cross-campaign duplicate prevention or to filter on large lists of criteria such as ZIP codes.
Deploying SuppressionList in LeadConduit Classic involves multi-destination behavior. Typically, the LeadConduit Classic campaign will utilize two delivery destinations, one for querying SuppressionList and one for adding data from the current lead to SuppressionList. Setting up each destination is somewhat similar, however between the two, the posting URLs, the request headers and the request bodies differ.
The first destination in your campaign will typically be a SuppressionList query. At this step, the list is queried to see if the data in a delivery parameter is present or not. If the datum is not in your SuppressionList, LeadConduit Classic will continue onto the next destination as specified. We recommend you create a SuppressionList QueryUrl, then have leadCOnduit CLassic's delivery destination call that QueryUrl to handle this function. See Creating and Working with Query URLs for the specifics on setting this up.
A separate LeadConduit Classic Custom Http POST delivery destination is used to add data to the current lead to your SuppressionList. This additional destination will add the value of the chosen delivery parameter to your SuppressionList. That way, the new lead data is pat of the List when the next lead comes is queried. See Adding and removing List items in the SuppressionList API documentation.