Do you want to check the Host header on all requests through the VIP and if it's one particular IP address, replace the value with a hardcoded value? If so, you can add an HTTP profile to the VIP and use a rule like this:
when HTTP_REQUEST {
Check if Host header matches 1.1.1.1.
Use catch to handle non-IP Host values.
If IP::addr matches 1.1.1.1, $result will be 1
if {not ([catch {IP::addr [HTTP::host] equals 1.1.1.1} result]) && $result==1}{
HTTP::header replace Host "www.example.com"
}
}
If that's not an accurate assumption of your scenario, can you clarify what you're trying to do?
Aaron