port 1: I’ve seen, with Wireshark, DHCP request from RB750 (to ISP in real life, to my test network for me). After, it was possible to ping this port, but nothing else (a firewall on thgis port I presume),
port 5: with wireshark: CISCO Discovery Protocol, but nothing else).
on other port, I don’t remember. Sorry.
I’ve opened the box, don’t see anything queer. I’ve closed the box. And now, It works:
I’ve seen the window that permit to erase the configuration,
and now the RB750 work fine.
I don’t know what has happened.
I’ve tested to erase configuration. All is fine. Now, with winbox.exe and the MAC address, I’m able to connect to the router.