How send a string to a specific IP's specific port when all pool members of a VIP are down?

Aaron: That sounds plausible, actually. You couldn't use LB::server pool in CLIENT_ACCEPTED really, since no pool would have been selected yet, but you could certainly use active_members if you know the specific pool anyway.

Something like (very untested):

when CLIENT_ACCEPTED {
  if {[active_members yourpoolname] == 0 } {
    TCP::collect
  }
}

when CLIENT_DATA {
  TCP::payload replace 0 [TCP::payload length] "down"
  node 10.10.10.1 12000
  TCP::release
}

Worth a shot at least. Try it out on a test VIP first as it's not tested, but that's the general idea.

Colin