SMB2: What’s new?

2 interesting article exploring new SMB2 and performance improvements

http://blogs.technet.com/josebda/archive/2008/11/11/file-server-performance-improvements-with-the-smb2-protocol-in-windows-server-2008.aspx

http://blogs.technet.com/josebda/archive/2008/12/05/smb2-a-complete-redesign-of-the-main-remote-file-protocol-for-windows.aspx

MS08-067: MS sneezes, Windows Admin have to work overtime

I am sure most of the IT guys supporting Windows out there would have been impacted by the release of the RPC patch, MS08-067: Vulnerability in Server service could allow remote code execution.

This has caused a flurry of activities with the top management in my firm with over night meetings and engineering trying to churn out the fix that can be deployed globally and top honchos deciding the best way to deploy this globally and have the servers rebooted.

WINS: Stumped (temporarily) by lmhosts (again…)

We had a issue yesterday when we cannot logon an old Windows NT server using our domain (let’s call it DOM1) account. The NT server is actually one of those leftover legacy NT domain BDC (lets call it RES1) that has trust to DOM1.

DOM1 was only upgrade to Windows 2000 AD last weekend and all access were tested successfully. Come Monday, apps team complained that they cannot logon with their DOM1 account to the NT server.

Our first thought is it has lost trust to the upgraded DOM1 domain, but we checked the PDC for RES1 and it was okay and this server (which is the BDC) was in sycn with the PDC in RES1.

MSCluster: Low free PTEs caused cluster service to disconnect

Back in the days when a lot of us are not sure what the 3GB switch really does and thought its must be set so that Windows can recognise 4GB RAM and above, a number of our application servers has been set with 3GB switches in their servers. This is one of the servers.

The other day one of the application cluster suddenly failed over. A quick check on the servers’ eventlogs show not issues with low non-paged pool memory or memory issues nor any network issues. The application logs was rather clean, other than a strange repetitive event from the MOM agent. We have a keep alive event which the MOM agent runs once a day, but I was seeing the same event running 2 twice every minute. On another server when had the same program we could see that the idling node had cpu running at 20% or more. Once we stopped the MOM agent, the cpu dropped to almost idle.

DFSR: TSM excluding replicated folders in backup

This is an issue if you are running DFSR and using TSM as a backup client, that TSM will not backup the replicated folders. Apparently DFSR sets up the keys in

HKLM\SYSTEM\CurrentControlSet\Control\BackupRestor e\FilesNotToBackup

and the TSM client honours these values and would exclude replicated folders from its backup.

There is an interim fix from TSM that should fix this issue.

The manual workaround is to stop DFSR before backup runs and start it after the backup is complete.

Network: The relationship between TCPWindowSize and DefaultReceiveWindow

We threw this question to our MS premier techie as we were troubleshooting some related issues and I thought his reply would be helpful for some of you out there.

Q1: What’s the relationship between the TCPWindowSize setting and the DefaultReceiveWindow handled by AFD.sys?

TCPWindowSize defines the amount of receive data (in bytes) that can be buffered during a connection at TCP/IP layer. The sending host can send only that amount of data before it must wait for an acknowledgment and window update from the receiving host. Windows will self-tune the TCP window size if it’s not explicitly defined in registry.

DefaultReceiveWindow defines the default receive buffer in Socket layer. By default, it’s 8 KB. Programs based on Socket gets data from that buffer. When a program receives more data than this buffer is configured to hold, all data received up to this count must be transferred to the program before receiving continues. When this happens, an acknowledgement will be sent to the source machine.

For example, if the application wants to read 32KB from the socket, it actually reads it from the buffer for 4 times (32/8 = 4).

CMD: Calling internal procedures in a batch file

I think a lot of Windows command batch scripters are not aware that you can call an internal procedure within a batch file. I sure did not find out about it until about 3-4 years ago.

Anyway, to get this work, first you must create a procedure. A procedure is like any standard batch script except that you must enclose it with a label at the head and goto label at the foot.

:MyProc

set myname=%1

@echo this is my first procedure

@echo my name is %1

goto :EOF

The start of the procedure is defined by the label :MyProc. A label always begins with a semi-colon. If you are accepting arguments in your procedure, you should treat it like a normal arguments, i.e. %1, %2, etc. You must end the procedure with a goto :EOF statement, if you don’t the procedure will continue running any commands below it.

Citrix: Logon Process Hangs at “Running Logon Scripts…”

We had a citrix server issue today. User complained of not being able to launch their published application.

So I fired up my citrix neighbourhood and tried connection to a citrix desktop. I could logon fine… however, it hung at “Running Logon Scripts…” dialog box. So I searched the knowledgebase in the net and go referred to CTX107433: The Logon Process Hangs At the “Running logon scripts…” Step. However, this KB don’t seem to resolve my problem and I am very sure that its not a printer driver issue.

Then I remember that we had resolved an issue with citrix before in one of my previous article on citrix. However for that case the citrix services could not start, in the current case, all the services started without issues. However, I still decided to have a poke at the path environment variable on this Windows 2000 box.

WinAdm: Disabling security settings information bar in IE7

Recently, I decided to upgrade my office’s XP machine’s Internet explorer from version 6 to verion 7 so as to that advantage of tabbed browsing. I am not a fan of IE7 and have been using Firefox mainly, but a lot of our firm’s site only runs on IE (dumb programming practice!) and so I still have to open multiple windows on my desktop.

The first time I fired up IE7, I am faced with the dreaded security settings information bar. And every new window or tab that I create the damn information bar keeps popping up. I cannot blame Microsoft really, it just too many stupid Internet users out there constantly compromising their own machine’s security and those of others (by being a zombie).

Anyway, I thought disabling the information bar would be a common enough complain to provide a solution. Sure enough, google find many complains about this issue, but almost none of those actually provide the correct solution to disable the security settings warning information bar.

Windebug: Server out of domain due to TCP/UDP port maxed

Last 2 weeks we had 2 different business services that faced similar issues. Essentially, their servers would drop off the domain, so when you tried to logon with your domain account, it will complain that the server is not in the domain.

I came to work on this when we had a number of servers from the same service team that had SCOM heartbeat issues. When we tried to logon to have to a look, we found that those servers had dropped out of the domain.