Using an iRule to specify multiple allowed ports for a virtual server

A BIG-IP generally has two "sides" for a traffic flow: the "client-side" (traffic flowing between client and the Virtual Server) and the "server-side" (traffic flowing between the BIG-IP and the next hop, often a pool member, but may be a routed next hop). When you select "port translation", the destination port on the server-side -- as it egresses the BIG-IP -- is set to match the pool member. Normally, if a Virtual Server is associated with a pool, it is providing a specific service. As such, a VS with a pool normally has a single port associated with it. Occasionally, the pool is actually next hop gateways. This is the ordinary use-case for a port-wildcard (i.e., the "all ports" option) Virtual Server that has an associated pool. In this configuration, it is not desirable to translate the port (and indeed, no port translation can occur because the pool member has its port set to 0). So, the default action when one sets "all ports" on the VS is to disable port translation, because this is the most common use-case for that option.