> This PR adds support for ZeroMQ to listen on multiple interfaces, just like the RPC server.
> Currently, if you specify more than one e.g. zmqpubhashblock paramter, only the first one will be used. Therefore a user may be forced to listen on all interfaces (e.g. zmqpubhashblock=0.0.0.0:28332), which can result in an increased attack surface.
> With this PR a user can specify multiple interfaces to listen on, e.g.
> -zmqpubhashblock=tcp://127.0.0.1:28332 -zmqpubhashblock=tcp://192.168.1.123:28332.
This is a backport of core#18309 [1/5]
https://github.com/bitcoin/bitcoin/pull/18309/commits/347c94f551c3f144c44e00373e4dd61ff6d908b7