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Implementing CIFS
It is one thing to be able to use Samba, Windows, and the Common Internet File System (CIFS) protocol. It is another thing entirely to understand CIFS with sufficient depth to begin coding using it. This is where Christopher Hertel's Implementing CIFS begins.
This thick book (over 600 pages) begins with a history of NetBIOS in the DOS era. It quickly progresses to NetBIOS over TCP/IP (which evolved into the current CIFS protocol). Hertel documents the beginnings of quirks that will last throughout the life of the protocol. There is an RFC that was proposed in 1987, but many vendors have added extensions to this. (It might surprise you to learn that Samba has added extensions, which are covered in Chapter 24).
After the basic overview, he quickly dives into real coding of an actual (though simple) implementation. This will be his style for the rest of the book (except for humorous asides now and then). An aspect of the protocol, such as Name Resolution, will be explained in some detail, and then expounded in actual code (and in a few cases pseudocode).
The detail is good but not overwhelming. Some people (with names like Jerry Carter or Andrew Tridgell) will want more depth than this book provides, but for with a protocol as varied as CIFS, choices have to be made. As the Samba website mentions, this book is written in "Geekish." The book covers aspects of older and newer SMB/CIFS implementations, including a description of the NTLM2 challenge/auth system.
One thing that should be noted is that the code examples work, but as the author points out, they usually have little or no error handling. This is common to many books, but it is something to remember.
Now, should you get this book? If you're just a user, you probably don't need it. But if you've ever wished you could understand the Samba technical mailing list, or wanted to know why it takes up to 15 minutes to see a new machine, then you'll enjoy this book. If you want to utilize CIFS in any manner (even if just implementing Samba for clients), I'd highly recommend reading this. It will help you to understand what is going on on your network, even if you're not writing the code yourself. And if you want to be a Samba coder, it is required reading.
What didn't I like? I first read the book in an airport, and found that it relies heavily on having access to a computer. I would have preferred more explanations of code fragments than was given. However, this is a minor issue; most people who are implementing CIFS will be using a computer! I was also left with a desire for more information, but the large Appendix D along with many sources recommended provide for further study.
As a bonus, Appendix A tells you how to make a good cup of Earl Grey tea! That alone to some would be worth the price of admission.
You can purchase Implementing CIFS from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
I know this is a difficult topic, but...Can't we just let CIFS to die, already?Alright, barring that, this really is a useful book. I wish I hadn't already learned it in the usual too-much-caffeine-for-rational-thought method.
Maybe a bit offtopic, but on my network I notice that Windows machines in the Network Neighborhood are slower to access than samba shares on linux machines. Go figure.
Linux Resources
And best of all it's available on O'Reilly's Safari service.
I've always wondered why on some machines it takes so damn long to browse the network on everything from 95 to XP -- most of the time I simply whimper and mumble incoherently waiting for it to eventually finish, but have never been able to diagnose the problem. Over the 'net it's even more agonizingly slow -- minute-long delays when pings are 30ms or less.
The post suggests that this book tells the answer, but do any enlightened here know some typical causes of the ridiculously poor performance?
-fren
"Where are we going, and why am I in this handbasket?"
This book is simply the best reference available for CIFS. I only say that because I have spent $$$ getting everything on the subject I can. With the recent changes in Microsoft licensing every sensible IT professional should be exploring alternatives. A SAMBA server is a great alternative. This book is all you need to go from knowing next to nothing to knowing enough to impress your geeky Network Admin friends.
This book is well written, clear and expansive. I didn't read it cover to cover (not at first anyway) I found pieces I needed, applied it, digested it, reviewed it and then went on to the next morsel I needed. If I missed something it was easy to find. By the way, it works with Win2K and WinXP neither of which is well documented by anyone anywhere.
The full text of the book is available online as well; I don't want to slashdot the site, but google for "implementing cifs".
For what purpose? Ruby is an esoteric language that hardly anyone uses and less people will use as the years goes on. This means that the code base will be unmaintainable.
Now Java or C# is a real option. Microsofts next implementation will be written in C# as a matter of fact.
Thanks
Bruce
Bruce Perens.
As good as Samba is... you know M$ is always hiding something about their network neighborhood protocol. It wouldn't surprise me if the code reads "If Samba wait 5 minutes"
However, I did need the sniffer method of reverse engineering for much of what the book did not cover. One complaint I had is that I needed more information on the higher level protocols such as LANMAN for handling printer queues and this information was either non-existent or schetchy in the book. Although the book is long, much of it is taken up by a CIFS document which you could download for free on the internet. So I do think that the description part of the book could be more extensive (Sorry Chris). Maybe in the next revision.
You might ask why I was implementing CIFS from scratch? Its a valid question, since Samba would/should be anyone's implementation of choice. I did it because we are developing a printer which is not GPL (and unfortunately not based on Linux). We are not using any GPL code in it, and so this was really the only choice besides buying it from someone (but where's the fun in that). I am planning on releasing this code under a BSD license, but it's not ready for prime time yet and I need to get back to it (in a couple of months).
So this was a really good book for CIFS implementors, but how many of those could there be?
One thing that should be added to that document is that all the Win9x machines should have the ability to be a Master Browser disabled (so long as there's at least 1 NT machine on the net).
Otherwise, eventually one of the 9x machines with think it's won the browse election even when that should be impossible. This screws the network neighborhood. Very longstanding bug going back to WfW. You can check the state of your network using the "browstat" tool that comes with the resource kit.
(Also, yer correct that NetBIOS or IPX will be faster than NBT for whatever reason. Make sure to adjust the "binding order" so that these protocols come ahead of TCP/IP. Can't recall exactly how to do this, sorry.)
This might not be realistic for a home net, but install WINS/DHCP if possible and put the clients into p-mode. (no NetBIOS broadcasts)
Bruce
Bruce Perens.
Alright, I can give a good reason. NFS does NOT authenticate, it blindly trusts UIDs.
So when I log into my friend's machine with his password, I'd be able to access my files on my machine as long as our UID is the same. Big trouble.
CIFS, on the other hand, has authentication, so I can put my SAMBA server on the wide-open internet and be somewhat sure that someone would need my password to get my files. Try that with NFS and you'd be owned (or fileless) in minutes.
Granted, there ARE ways to lock NFS down, and there are good arguments that maybe the modern file server SHOULDN'T authenticate, it should rely on another layer to handle that, but until it's easy as pie to get a Kerberos/PAM/NFS system working (no small task today), I'll stick to CIFS.
"Sometimes, I think Trent just needs a cup of hot chocolate and a blankie." -Tori Amos on Nine Inch Nails
There will be bugs in the M$ nfs server code. Will Windows Update patch them?
The patch against SQL Slammer had been out for six months before Slammer took down South Korea and invaded a nuclear power plant. I don't want to install anything that requires special patching procedures.
I was hoping that 3.0 would have been renamed as CIFiliS.
I mean, it would give the right impression about the Windows native file sharing protocol, and would be great for PHB's.
PHB: "Did you get that Samba thingy working on the server?"
IT Guy: "No, the server has CIFiliS"
PHB: "Oh. I'm sorry. You should run one of those virus checker things."
-- Len
Actually Apple gives away (BSD Style license) a code sample for implementing rendevous services. That should mean that anyone can/should implement rendevous if they need network discovery.
Go out and get sailing!