iRule

mgrdta If the F5 is not your perimeter device this should be blocked on your firewall or router depending on what you have to allow traffic in. As Daniel_Wolf stated, you are better off blocking this as a packet filter but you can create an iRule to block traffic from whatever source you would like. If you went the iRule route you might want to make it part of your build document so that when adding a new virtual server that you have an iRule that will always be applied no matter what and if you will eventually add more IPs to be blocked you should utilize a data-group to reference in your iRule for blocking sources.