TCL error with an universal irule

Is there a reason you are adding persistence in the http response event?

​I think since you want to create persistence from the client side information (XFF/src address) adding it in the http request event would be enough.

​

when HTTP_REQUEST { 
 if {[HTTP::header X-Forwarded-For] != ""} then {
persist uie [lindex [ split [lindex [HTTP::header values X-Forwarded-For] 0] "," ] 0]
    } else {
persist uie [IP::client_addr]
}
}

​

​