Cannot reach Dude CHR in headless VirtualBox

This is part of a saga about managing RouterOS updates, which is a sad story - anyway attempt no 4 is to set up the Dude for that purpose and others.

I downloaded chr-6.40.8.vdi and set up a guest in Virtualbox using the command line - this is in a headless, Linux server host OS. The guest starts fine, but I can’t reach it…

It appears it doesn’t have any IP address by default and must be accessed by console. That is a bit crazy (192.168.88.1 might be helpful guys) but whatever. And, since the Virtualbox host is headless, I don’t have a GUI console available.

My problem is that although VRDE is listening on the specified port 8001 as shown by lsof (on *:8001), it won’t allow an RDP connection. I have:
Video mode: 720x400x0 at 0,0 enabled
VRDE: enabled (Address 0.0.0.0, Ports 8001, MultiConn: on, ReuseSingleConn: off, Authentication type: external)
VRDE port: 8001
Video redirection: disabled
VRDE property: TCP/Ports = “8001”
VRDE property: TCP/Address =
VRDE property: VideoChannel/Enabled =
VRDE property: VideoChannel/Quality =
VRDE property: VideoChannel/DownscaleProtection =
VRDE property: Client/DisableDisplay =
VRDE property: Client/DisableInput =
VRDE property: Client/DisableAudio =
VRDE property: Client/DisableUSB =
VRDE property: Client/DisableClipboard =
VRDE property: Client/DisableUpstreamAudio =
VRDE property: Client/DisableRDPDR =
VRDE property: H3DRedirect/Enabled =
VRDE property: Security/Method =
VRDE property: Security/ServerCertificate =
VRDE property: Security/ServerPrivateKey =
VRDE property: Security/CACertificate =
VRDE property: Audio/RateCorrectionMode =
VRDE property: Audio/LogPath =

tcpdump shows my Windows workstation RDP client exchanging 20-odd TCP packets with the Dude server, but RDP then reports “the client can’t connect”. Similar result using rdesktop on Linux to localhost:8001.

Can anyone help identify what’s going wrong here? Thanks in advance!