Do you have a virtual server defined on port 13081? Or is it matching a wildcard port virtual server? If the VS is defined on port 13000 your requests on port 13081 shouldn't be using this VS.
To handle a range of 80 ports, you can change the virtual server to listen on port 0 (any port) and then use an iRule to block all other ports. Do you want to have LTM perform destination port translation? Or do you want LTM to just pass through the port of 13000 to the pool member on 13000 and 13001 to the pool member on 13001? If the former, what's the logic for doing the port translation?
Here's an example of the iRule to only allow connections through on ports 13000 - 13080:
when CLIENT_ACCEPTED {
if {[TCP::local_port] >= 13000 and [TCP::local_port] <= 13080}{
Do nothing and allow the connection through to the pool
} else {
Reset the connection
reject
}
}
Aaron