how to deny ip visit application

Hello Yuanqiang,

It is better to check in your irule the FQDN and based on the FQDN drop or do nothing.

when HTTP_REQUEST {

    if { ! ( [string tolower [HTTP::host]] eq "app.domain.com" ) } {
        drop 
        log local0. "connection dropped from client for accessing [HTTP::host]"
    }
}

By doing this, you prevent clients to connect via IP directly and also via other FQDN (if they changes their host file for example).

Hope it helps

Regards