I have cloned the cpp-ethereum for Linux (Ubuntu) from git as follows as

$ git clone https://github.com/ethereum/cpp-ethereum

$ cd cpp-ethereum

cpp-ethereum$ git checkout 5669c209f4f8dbb7dc3f744e8e2a9c92f1104ca3

cpp-ethereum$ git checkout -b develop

cpp-ethereum$ git submodule update --init --recursive

cpp-ethereum$ mkdir -p build cpp-ethereum$ cd build

cpp-ethereum/build$ git clone https:///github.com/cinemast/libjson-rpc-cpp

cpp-ethereum/build/$ cmake .. && make

cpp-ethereum/build/$ eth

It shows the following error



12:27:18|p2p Couldn't punch through NAT (or no NAT in place).



How to solve this problem?