Sticky filters

The NS1 Filter Chain offers three types of "sticky" filters: Sticky Shuffle, Group Sticky Shuffle, and Weighted Sticky Shuffle.

Sticky filters aim to distribute traffic across multiple answers while ensuring DNS queries from the same source IP address are handled consistently over time.

• Sticky Shuffle filter
  Performs a shuffle to ensure that answers are always returned in the same order for an individual requester or subnet.
  
  
• Group Sticky Shuffle filter
  Ensures that the answer groups are always returned in the same order for an individual requester or subnet. Answers within the groups are returned in any order. Often, this filter is used alongside the "Select First Group" filter to ensure the same requester is directed to the same group of answers.
  
  
• Weighted Sticky Shuffle filter
  Like the standard "Sticky Shuffle" filter, except that answers are shuffled randomly based on the weight metadata field, the shuffling is consistent for the individual requester or subnet. Note that changing the weight metadata or answer pool will re-shuffle answers for the requester/subnet. 

Note that since the NS1 platform is queried by DNS resolvers and not directly by end-users, the stickiness enabled by these filters is with respect to the DNS resolver's IP address and not that of the end-user. The exception is when the DNS resolver supports edns-client-subnet (ECS), and ECS support is enabled for the DNS record, in which case, the stickiness is applied to the IP prefix contained in the ECS data sent in the DNS query.