Posts Tagged ‘SMB’

Server Message Block (SMB) Dialects and Oplocks

July 2nd, 2011 No comments

This post describes typical message exchange sequence for a client connecting to a user level server, opening a file, reading its data, closing the file, and disconnecting from the server. Opportunistic Locking (Oplocks) are also explained.

You can also refer tothis capture: Download smbtorture from Wireshark Wiki to further understand the SMB dialogues. The capture was made using the Samba4 smbtorture suite, against a Windows Vista beta2 server. Read more…

Categories: Protocol Analysis Tags: ,

Using Wireshark to examine SMB Signing Requirements

April 13th, 2011 No comments

When a client connects to a server using SMB it sends a “Negotiate Protocol Request”.¬† In response to this, the server replies with a “Negotiate Protocol Response”.¬† This response reveals whether SMB signing is enabled and whether it is required at the client, the server, or both. Read more…

Categories: Protocol Analysis Tags: ,

SMB Opportunistic Locking

November 22nd, 2010 No comments

Concurrent writes to a single file are not desirable in any operating system. To prevent this, most operating systems use locks to guarantee that only one process can write to a file at a time. Operating systems traditionally lock entire files, although newer ones allow a range of bytes within a file to be locked. If another process attempts to write to a file (or section of one) that is already locked, it will receive an error from the operating system and will wait until the lock is released. Read more…

Categories: Network Design Tags:

Disabling SMB v2.0 on Windows Vista / Win7 / Server 2008

October 14th, 2010 No comments

Server Message Block (SMB) Protocol  is the file sharing protocol used by default on Windows-based computers. SMB 1.0 was designed for early Windows network operating systems such as Microsoft LAN Manager and Windows for Workgroups, but until Windows Server 2008 and Vista, all Microsoft-based operating systems continued to use it more or less in its original format.

SMB 2.0 was introduced in Windows Vista and Windows Server 2008. SMB 2.0 is designed for the needs of the next generation of file servers. Windows Server 2008 and Windows Vista support both SMB 1.0 and SMB 2.0 in order to preserve backward compatibility. Read more…