Chapter 13. Protocol Negotiation

I don't have an accent .

Oh yes you do.

CIFS is a very rich and varied protocol suite, a fact that is evident in the number of SMB dialects that exist. Five are listed in the X/Open SMB protocol specification, and the SNIA doc published ten years later lists eleven. That's a bigbunch, and they probably missed a few. Each new dialect may add new SMBs, deprecate old ones, or extend existing ones. As if that were not enough, implementations introduce subtle variations within dialects.

All that in mind, our goal in this section will be to provide an overview of the available dialects, cover the workings of the NEGOTIATE PROTOCOL SMB exchange, and take a preliminary peek at some of the concepts that we have yet to consider (things like virtual circuits and authentication). For the most part, the examples and discussion will be based on the "NT LM 0.12" dialect. The majority of the servers currently available support some variation of NT LM 0.12, and at least one client implementation (jCIFS) has managed to get by without supporting any others. Server writers should be warned , however, that there really are a lot of clients still around that use older calls. Even new clients will use older calls, simply because of the difficulty of acquiring reliable documentation on the newer stuff.