What is [::]:0 address in bitcoin debug.log? I am trying to run and connect multiple nodes on a single machine, i.e different nodes using different ports. I am having trouble in connecting the nodes and making them talk to each other. While debugging, I inserted a LogPrintf("%s\n",addr) in the while loop of ThreadOpenConnections() in net.cpp file.

The output in the debug.log file is always [::]:0. What does this address mean ? Is it for localhost representation or something else ?
[::] is IPv6's version of localhost (0.0.0.0).