Network Broadcast

[Bluedrakie]

Hi Guys

Simple version of our network layout

10.4.0.0/24 natted to 10.20.0.0/24 testing environment, replica of live environment
10.4.0.0/24 live environment
10.4.1.0/24 user network

Both test and live environment are on the same domain, but the ad servers and testing servers are completely separated by natting and a firewall to the live servers. The live environment cannot see the testing environment and vice versa, only the users network can see both networks.

Now here is the problem that im trying to understand

User Jack opens a file share to serverx.domain.com on the live environment via dns name.
User Jack opens a file share to serverx.domain.com on the testing environment via IP address.

User Jack copies a large file between the two file shares, and all of a sudden there is a massive network broadcast, and very bad network latency through out all networks.

Can someone please explain what is happening so I can try get a better understanding of this

Thanks for all the help in advance