Thank you very much Dave.
Yesterday I used the netstat command and discovered the VI client uses the https connection, so the port 443 to reach the esxi host. I forwarded it in my router and then....I got access from a remote site (my home!).
I did a mistake trying to reach the host from a client inside the LAN but pointing to the public ip address of the host. I.e. I tried to test the remote from inside the lan and it didn't work.
I went home, tried from there and everything went perfect (ssh - either on the host, either on the virtual server, vnc, etc...). So it appears that the esxi does NOT have a firewall at all. Only the file inetd.conf has some influences on enabling/disabling services implemented in the esxi host (I read tftp, ssh and some others) as written in the first page of this discussion. Thank you.