Delay in packet pass-through

There will be a small delay while passing through any piece of networking equipment, but this should be in the order of less than a millisecond.. we certainly don't (and can't, as Amy's pointed out) have any way to delay a packet for 1000 milliseconds in the fastL4 profile. I suggest you carefully compare the network paths taken between packets that go via the LTM, and those that do not. You could also run tcdpump on the LTM and look at the timestamps of the packets arriving on the client side, compared with the timestamp of the same data leaving on the server side. Or capture one hop away from the LTM, then two, etc. See if you can find what's happening that is different from the path that works.