The "IP::client address" in iRules drop packet from broadcast address or not?

when CLIENT_ACCEPTED {
if { [class match [IP::client_addr] equals DATA_GROUP] } {
forward
} else reject
}

Sets the connection to forward IP packets. This is strict forwarding and will bypass any pool configured on the virtual server.

The request will be forwarded out the appropriate interface according to the routes in the LTM routing table. No destination address or port translation is performed.

If the client ip matches if condition, it forwards. In your case the ip comes in the /24 range. If it doesn't match, it rejects.