Restrict Traffic To VIP By Subnet

Just go with a datagroup with Irule method. So that you can add more IP's in the blacklist group on the file. You need not keep editing your irule.

Create a datagroup called blacklist subnet, make sure its type IP.

type: ip

ltm data-group internal blacklist_subnet {
records {
20.20.20.0/32 { }
30.30.30.30/25 { }
}
type ip
}

Then create your irule like below,

when CLIENT_ACCEPTED {
if { [class match [IP::client_addr] eq blacklist_subnet] } {
	log local0. "Client IP - [IP::client_addr] is blacklisted. Dropped traffic"
    drop
}
}