load balance ICMP echo requests to pool members

Hi there,

I'm trying to setup a virtual server which will forward ICMP to pool members and let them handle answering ICMP instead of letting the BigIP handle ICMP itself. My plan was to:

1. disable ICMP echo in the virtual address setting:

   ltm virtual-address 10.2.1.23 {
      address 10.2.1.23
      icmp-echo disabled
      mask 255.255.255.255
      traffic-group traffic-group-1
   }

2. Define an appropriate pool with port "any":

   ltm pool test {
   members {
       docker_host1:any {
           address 10.100.1.10
       }
   }
   }

3. Define a fast-l4 virtual with ip-protocol icmp and destination port any and attach the pool to it:

   ltm virtual trestdjo {
   destination 10.2.1.23:any
   ip-protocol icmp
   mask 255.255.255.255
   pool test
   profiles {
       fastL4 { }
   }
   source 0.0.0.0/0
   vlans {
       client
       server
   }
   vlans-enabled
   }

However, this virtual does not catch the pings coming in from vlan "client" to destination address 10.2.1.23. I can see the pings arriving in vlan client when running tcpdump, but they are left unanswered. The hit counts of the virtual above are not incrementing, so it doesn't seem to match the traffic. I'm unsure whether fastL4 is even capable of handling ICMP traffic, but it is the only type of virtual that allows me to specifiy ICMP as IP protocol (type standard doesn't) and attach a server pool to it.

Any idea how to achieve the desired behaviour? Many thanks in advance.

Regards

Martin