Analysing network traffic – troubleshooting


Many occasions while configuring the FAST SSA’s with custom pipelines, crawl rate will be very less.

Sometimes, the issues might be due to network settings. Follow these steps to debug these issues.

Please see the steps below in order to configure Network Monitor:

1a. Turn off TCP Chimney if any of the machines are Windows 2003
Option 1) Bring up a command prompt and execute the following:
Netsh int ip set chimney DISABLED
Option 2) Apply the Scalable Networking Patch – http://support.microsoft.com/default.aspx?scid=kb;EN-US;936594

1b. Confirm that TCP Chimney is turned off if any of the machines are Windows 2008 and the driver is older than January 2010 (see http://support.microsoft.com/default.aspx/kb/951037 for more details)
a) bring up a command prompt and execute the following:
netsh int tcp show global
b) if it turns out TCP Chimney is on disable it
netsh int tcp set global chimney=disabled

2.  Turn off TCP Offloading/Receive Side-Scaling/TCP Large Send Offload at the NIC driver level

3.  Retry your application.  Don’t laugh – many, many problems are resolved by the above changes.

4.  Download Network Monitor
(http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=983b941d-06cb-4658-b7f6-3088333d062f)

5. Install Network Monitor on both the client and server experiencing the problem.  If you are not able to install it on the server you can install it on another machine that is connected to the same hub as the server or to the admin port of the switch that the server is on.  If you go this route you must synchronize the time between the client, server, and this third machine.

6.  Synchronize the clocks on the Client and SQL machines
a)  At one of the machines bring up a command prompt and execute the following:
Net time <\\machinenamewewanttosynchwith> /set /yes

7. Using the NMCap command-line utility, start the chained trace (chained = create a new capture file after reaching the “Temporary capture file size” rather than overwriting the current capture)
a) [Netmon 3 installation folder]\NMCap /network * /capture /captureprocesses /file test.chn:25M /UseProfile 45c7af5a-d264-4243-90df-fb97082c52ac (creates 25 MB chained files)
b) NOTE:  YOU MUST USE THE .CHN EXTENSION TO CAPTURE CHAINED TRACES
c) NOTE:  The target folder must exist for NMCap to create the trace file

8. Flush DNS
a) ipconfig /flushdns

9) If dealing with an authentication failure, you will now want to purge the Kerberos tickets
a) klist tickets tgt purge

10. Get the IP addresses of the client and the server
a)  ipconfig /all on the client > client.txt
b)  ipconfig /all on the server > server.txt

11. Reproduce the problem, please note the exact time the problem reproduces.  Also, please note the exact error message.

12. Stop the trace by hitting Ctrl-c in the command-line window

IMPORTANT: Please remember to let me know the IP addresses of the server and client as well as the time that the problem occurred.

More information can be found at:

http://blogs.technet.com/netmon/archive/2006/10/24/nmcap-the-easy-way-to-automate-capturing.aspx

OR

by running the command-line switch /examples

OR

by running the command-line switch /?

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