Strangely enough, it has started to work properly and I didn't even touch my code just had it sitting there in the loop/ping circuit it was performing and capturing with wireshark.....that is quite odd!

"Hi, so I have my .NET node communicating on the P2P network just fine, so I figured as I'll now start looking at making and validating transactions etc I should probably migrate to test net. Now I see that we are up to the third generation testnet testnet3, and I am sending my messages now using packet magic 0x0b110907 and I'm using Wireshark and I can confirm that my messages are going out with that packet magic.

Now what is interesting is that when I try connect to a test node obtained from DNS seed testnet-seed.bitcoin.petertodd.org, I send it a version message with the testnet3 packet magic, yet I get no verack or version in response???? In fact, the only thing I get back is a ping and then the connection is severed by the remote node.

What is going on? Also, it works fine with the mainnet packet magic value of 0x0f9beb4d9 and I am debuging my code and ensuring it is looking for the testnet3 packet magic, but I am not getting a response from the node?"