Universal Persistence & FASTL4 profiles

While technically you can attach a universal persistence profile to the L4 virtual server, it will not work since the information you want to persist on is in the header which requires access to layer 7 (specifically you need a http profile which is not available when using a L4 virtual server).

Here is a good document on universal persistence and how it is typically used.

But, the irule I want to use does not need to monitor HTTP headers:

when CLIENT_ACCEPTED { 
    set client_ip_port "[IP::client_addr]:[TCP::client_port]"
    persist uie $client_ip_port
}
when SERVER_CONNECTED {
    persist add uie $client_ip_port 3600
}

CLIENT_ACCEPTED and SERVER_CONNECTED are all TCP events, aren't they ? I don't need the HTTP header, do I?

Yes, you are correct. CLIENT_ACCEPT and SERVER_CONNECTED are L4 events, so it will work with Fast L4 (no http profile required).

See: https://devcentral.f5.com/questions/what-exactly-does-fastl4-profile-do

Excellent!