BIG-IP has feature persistence profile, it uses for keep existing session on a member. For example : Pool have 2 members (A and B), for example request will redirect to A, but sometimes it can redirected to B for a while, it cause client losing connection to A. How to create persistence profile based on source address. - Go to Local Traffic -> Virtual Servers -> Profiles -> Persistence - Click create to make a new persistence profile - Change Persistence Type to "Source Address Affinity" - Make sure that Parent Profile "source_addr" - Don't forget to give a name to your new profile Assigning Persistence Profile to Virtual Servers. - Go to one of your virtual servers, and then go to tab "Resources" - Assign Default Persistence Profile with your new persistence profile.