Cookie Persistence iRule not working

Hi Noyan, if i check well your config, your cookie used in the iRule is named ASP.NET_SessionId. I assume it is containing the "application" state for the client.

The cookie you use in the resource, is the standard BIGIP-Cookie (with the cookie insert method). So it is named differently (bigip-cookie or something like that). This cookie contains the IP address of the destination pool member for the different connections the client can create for the other HTTP connections.

The issue i see is that if the application change the cookie content, you will never change from one server to another, which is perhaps not an issue for you. But the other issue is that if the BigIP Cookie changes (browser has been closed and then reopened for example), then even if you send your "ASP.NET_SessionId" that has not changed (except if it is also a session cookie that was deleted when the browser was closed), you will land on a different pool member due to the Load Balancing algorithm (no cookie, then LB).