BIG-IP connection mirroring in public cloud doesn't work, but why?

Thanks for the writeup MichaelOLeary.

I will add that there are some other things to think about when looking to use connection-mirroring (TL;DR most times it's unnecessary):

• SSH and RDP type services do have the ability to set keep-alives 
  • in SSH for example you can set the following in your ~/.ssh/config

    # Settings 10 retry messages at one every 60sec  
    ServerAliveInterval = 60
    ServerAliveCountMax = 10

• Ensuring that your fastL4 servers have the ability to pass flows in flight (e.g. the loose-initiation and loose-strict values)
• non-HTTP and Standard Virtual Servers that need connection mirroring definitely come with a caveat for the type of app and protocol (databases for example)

Having said all that, if you do have a fastL4 wildcard routing-type Virtual Server *most* protocols tend to be fine unless its something in the middle of its transaction (e.g. database write, etc.)

I've helped customers deploy BIG-IP in Carrier Grade NAT scenarios (which is similar in some respects to a cloud-based environments) to be able to "seamlessly" fail devices or reboot so that subscribers are generally unaware their Internet is down: https://www.youtube.com/watch?v=hsb0OtqO_AM&list=PL5jC9WagzrjExq85JuWQHSUm9PegO3JmR&index=16