To be more precise... SSH is only used to launch Julia on the worker nodes. Afterwards, Julia sets up a socket on both nodes and passes messages through that. If the sockets can't be bound, because of a restrictive firewall for instance, Julia would try for 60 seconds and then time out.
At first, I was wondering if Julia would erroneously try to resolve any machine name it finds. But since you tried to add the hostname and the IP in /etc/hosts, without any improvement, that certainly means that the resolution is OK (not sure though : dig do no check /etc/hosts). But whatever, by accessing the node, you can see if a socket has been set up by Julia.
