Step 4 in the single masternode setup has an error in it. Where it says should also include the port. This took me a few hours to figure out and kept giving me the 0 port error.
Here is my darknet.conf
addnode=108.61.151.69
addnode=173.245.158.8
addnode=coin-server.com
addnode=185.117.72.180
addnode=164.132.25.216
addnode=5.39.8.251
addnode=164.132.143.9
addnode=46.8.44.81
addnode=104.172.24.79
addnode=2.230.243.216
listen=1
server=1
daemon=1
port=51472
logtimestamps=1
maxconnections=256
rpcuser=s0methingCrazyAndRandom
rpcpassword=s0methingCrazyAndRandom
rpcport=51470
rpcallowip=127.0.0.1
masternodeaddr=:51472
masternode=1
masternodeprivkey=XXXXXXXXXXXXXXXXyourMasternodePrivkeyXXXXXXXXXXXXXXXXXXXXX
I also added to the file for masternodes.conf (not sure if this was necessary for a single node):
# Masternode config file
# Format: alias IP:port masternodeprivkey collateral_output_txid collateral_output_index
# Example: mn1 127.0.0.2:51474 93HaYBVUCYjEMeeH1Y4sBGLALQZE1Yc1K64xiqgX37tGBDQL8Xg
MasterNode 127.0.0.1:51472 masternodeprivkey collateral_output_txid collateral_output_index
You shouldn't need the port number in the Darknet.conf file (but won't hurt to add it) but you will need the port number in the masternode.conf file. You can not use loopback addresses, or internal IP addresses as the external/masternode/bond or you will have issues as your nodes will be banned from the network.