- install bitcoind by sudo apt install bitcoind in Ubuntu 16.04 server amd64(https://bitcoin.org/en/full-node#ubuntu-1410)
- bitcoind --version show v0.13 ga402396
- bitcoind -daemon -zmqpubhashblock=tcp://127.0.0.1:28332 -zmqpubhashtx=tcp://127.0.0.1:28332 after download, blocks file is 89G. and the bitcoin.conf only have rpcuser=xxxyyy and rpcpassword=xxx123 should add server=1 to bitcoin.conf?
- git clone https://github.com/bitcoin/bitcoin
- cd bitcoin/contrib/zmq and pip install zmq, then do python zmq_sub.py and we can't receive anything in long wait. How can we receive hashtx and hashblock from bitcoind? Should i install libzmq3-dev? Is libzmq3-dev only for compile bitcoind and don't need in runtime?
The PPA you have installed (https://launchpad.net/~bitcoin/+archive/ubuntu/bitcoin/+packages) is not compiled with ZMQ support (It should in future).
You need to self-compile bitcoin v0.13.0 or use one of the "official" binaries: https://bitcoin.org/bin/bitcoin-core-0.13.0/
EDIT: since 0.14, ZMQ support is available via the PPA