Looking at a capture and seeing a "NBSS Continuation Message" port 445, but I cannot find any reference anywhere to what this might mean.
I assume it's a normal message for the NetBIOS Session Service, but can't find a definition of it anywhere.
Can someone point me to further details?
It could be a client trying to connect to a samba share with a "negotiate protocol request" using naked tcp. If the smb share doesn't respond to smb over naked tcp, then it might look like a continuation message.
Typically, there would have been a preceding packet with full header information about the request/response to this "continuation message". Wireshark would be able to detect it automatically and reassemble the PDU labeling the packet
[TCP segment of a reassembled PDU]
. But in your case, apparently either the packet starting the transmission got lost or the NBSS dissectors / reassembly features of Wireshark have been disabled.