Moving Interoperability Documentation Help (dochelp) to bcc. Hi, all
This is an expected behavior. I have a blog about this topic that should explain the behaviors you have observed (http://blogs.msdn.com/b/openspecification/archive/2009/04/10/smb-maximum-transmit-buffer-size-and-performance-tuning.aspx). Jeff, Please let me know if you have more questions. I can provide you more clarification if needed. Thanks! -------------------------------------------------------------------- Hongwei Sun - Sr. Escalation Engineer DSC Protocol Team, Microsoft hongw...@microsoft.com Tel: 469-7757027 x 57027 Exceeding your expectations is my highest priority. If you would like to provide feedback on your case you may contact my manager at allis...@microsoft.com. --------------------------------------------------------------------- -----Original Message----- From: cifs-protocol-boun...@cifs.org [mailto:cifs-protocol-boun...@cifs.org] On Behalf Of Shirish Pargaonkar Sent: Monday, June 20, 2011 4:16 PM To: Jeff Layton Cc: Interoperability Documentation Help; cifs-proto...@samba.org Subject: Re: [cifs-protocol] SMB1 maximum packet size with signing enabled On Mon, Jun 20, 2011 at 2:56 PM, Jeff Layton <jlay...@samba.org> wrote: > On Mon, 20 Jun 2011 11:42:01 -0700 > George K Colley <gcol...@apple.com> wrote: > >> >> On Jun 20, 2011, at 6:43 AM, Jeff Layton wrote: >> >> > -----BEGIN PGP SIGNED MESSAGE----- >> > Hash: SHA1 >> > >> > I've been doing some testing with signing enabled and have found >> > that >> > win2k8 seems to consistently return STATUS_ACCESS_DENIED whenever I >> > send it a SMB that's larger than 16704 bytes. It seems to have no >> > issue with larger sized SMBs when signing is disabled. >> > >> > It seems sort of like a protocol violation since the NEGOTIATE >> > response from the server has the CAP_LARGE_READX and WRITEX bits >> > set. It's possible though that I've missed something in the spec. >> > >> > In any case, my questions: >> > >> > 1) is this a known limitation in windows, or a bug? >> This has been a known issue for a very long time. When signing is on you >> need to use the negotiated buffer size not the Large CAP size. >> > >> > 2) is this common to all (most?) versions of windows? >> Yes >> > >> > 3) is there some way we can detect what the server's limit is in this >> > situation? >> If the UNIX CAPS is not set and they have signing on then I turn off >> CAP_LARGE_WRITEX. Note this does not affect CAP_LARGE_READX. >> > > Thanks George... > > So we need to use the max buffer size advertised by the server? When I > look at captures, I can see that the server is sending a max buffer > size of 4356 bytes in the NEGOTIATE reply. That's quite a bit smaller > than the max size that gives me errors (~16k). > > Also, I'll note that Shirish looked at some captures between windows > and found that sends around 16k packets when signing is negotiated. In negrprot response (from a Windows 2008 server to a Windows 2003 client), max buffer size is 16634, max raw buffer 65536 and unix extensions not supported, large read andx and large write andx supported. > I'll bet we can exceed that size by some amount, it would be good > though to know how big a size we can get away with... > > Thanks, > -- > Jeff Layton <jlay...@samba.org> > _______________________________________________ > cifs-protocol mailing list > cifs-protocol@cifs.org > https://lists.samba.org/mailman/listinfo/cifs-protocol > _______________________________________________ cifs-protocol mailing list cifs-protocol@cifs.org https://lists.samba.org/mailman/listinfo/cifs-protocol _______________________________________________ cifs-protocol mailing list cifs-protocol@cifs.org https://lists.samba.org/mailman/listinfo/cifs-protocol