Windows network package capture without installing anything (on the server)

I like Wireshark. But I don’t like to install software on a server for troubleshooting purposes. Especially when you need software like PCAP to sniff some network data.

But what you can do is capture data data with netsh, copy the data to your workstation, convert the data so you can read it with wireshark and do you thing.

Capture the data

Run this command to capture the data (elevated command prompt)

netsh trace start capture = yes ipv4.address = x.x.x.x

And stop the capture when you are done

netsh trace stop

Copy the files to you computer

Convert the capture

Download the etl2pcapng converter from the MS Github repo: https://github.com/microsoft/etl2pcapng

Convert the data

etl2pcapng.exe NetTrace.etl out.pcapng

You can open the out.pcapng file and do you thing.

Happy Troubleshooting!

Slow initial RDP connection

For me, this was a pain in the ass for a long time. When I connect to a Windows server through RDP/RDS it sometimes takes more than 2 minutes to connect to a server. Today after some waiting, and waiting and some more waiting I did a deep dive with Wireshark to figure out why it was so slow.

My setup

  • Azure domain joined Windows 10 device (Laptop)
  • Connection over a Cisco Anyconnect VPN
  • Remote Desktop Manager (Devolutions)
  • Native RDP client
  • MremoteNG

Remote VS local

I know for sure the issue should be in my setup. Because when I connect first to a jump host (RDP) and then connect to other domain-joined servers everything was connected almost immediately after I put in my user credentials.

What to do (TL;DR)

There are four things you have to modify to speed up the initial remote desktop connection speed:

  1. Disable SSL / TLS1.0
  2. Disable Netbios on the VPN network adapter
  3. Disable automatic proxy settings in Windows
  4. Change the credential to domain.local\admin or [email protected] instead of domain\admin

Disable SSL / TLS1.0

No, you don’t have to negotiate what protocol you have to use to connect a server. Use TLS1.2 or I don’t want to connect with you 😉 So:

How to

  • Start > Run > Regedit
  • Go to: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Client
  • If the TLS 1.0 and Client folders doesn’t exists create these keys
  • Create a 32 DWORD value with the name Enabled
  • Value data: 0 (Hex)
  • Restart the client
Enabled = 0

Disable Netbios on the VPN adapter

What I was seeing in my Wireshark capture is that RDP was trying to broadcast to get information over NETBIOS. You have a DNS server so you don’t need a legacy broadcast protocol! Unfortunately, I don’t have any screenshot of the capture but you can always check yourself 😉

How to

Change the VPN Adapter and reboot the computer:

Disable Netbios

Disable the proxy

After connection to a server with RDP and you enter the credentials Windows is trying constantly to WPAD.domain.local to autoconfigure itself. WPAD stands for Web Proxy Auto-Discovery and I think you never want to autoconfigure a MITM ehh proxy device. You always want to have full control of your device. So, disable this to speed up the connection and make your device more secure.

Wireshark Capture WPAD A record

How to

  • Go to settings
  • Search for proxy
  • Switch the Automatically detect settings to Off
  • Restart Windows
Turn WPAD off

Change the login name

I found out that this is the most annoying and time consuming one. I always use DOMAIN\User when I connect to a server. But this is what happens:

Domain.Domain.TLD

Kerberos is doing a DNS query on _kerberos._tcp.dc._msdcs.domain.domain.tld and of course he will never can find that double domain A record. But if you change the logon name to domain.tld\admin or [email protected] Kerberos will find the A record and connects immediately 🙂

Top speed!

Kerberos

And even now it’s possible to tune the Kerberos authentication further and fix the last KRB5KDC_ERR_PREAUTH_REQUIRED error you can see in the screenshot. Maybe next time but for now I’m happy with the initial connection speed 🙂

Happy hack ehh… connecting!

Policy WSUS: “Automatically download updates and install them on the schedule specified below” don’t work…!!!?!

So I configure a “configure automatic updates” policy for testing purposes but the auto-update and installation won’t work. The main cause….? Lack of patience 😉

How this Policy works (source):

The Windows Update Agent periodically checks the WSUS server for updates. Updates it finds, it reports state for: Installed, Not Installed, Not Applicable. If a “Not Installed” update is approved and available, the WUA queues the installation files for download if the Configure Automatic Updates policy is set to AUOption ‘3’ or ‘4’.

The download occurs via Background Intelligent Transfer Service (BITS) subsequent to the WUA finding the update as available for download.

When the download of the update is completed, the WUA does one of two things:

  • If the Configure Automatic Updates policy is set to AUOption ‘4’, then the WUA will schedule the update for installation at the scheduled time. This scheduled installation does NOT require access to the WSUS server to be conducted.
  • If the Configure Automatic Updates policy is not set to AUOption ‘4’, then the update will be retained on the client computer until a user launches the Windows Update applet from Control Panel and initiates the installation.

So bottom line; the updates must first be downloaded on the client and ONLY then will Windows apply the “Automatically download updates and install them on the schedule specified” action

To force a client (source):

$updateSession = new-object -com "Microsoft.Update.Session"; $updates=$updateSession.CreateupdateSearcher().Search($criteria).Updates
Start-sleep -seconds 10
wuauclt /detectnow
wuauclt /reportnow
c:\windows\system32\UsoClient.exe startscan

After this commands BITS will download the updates and prepare the installation. When you start Windows update you can see the available update

The default of the WSUS communication check-in (report and detect) is 22 hours. If you don’t want to wait so long you can change the “automatic updates detection frequency” to every hour (do not to this every hour on production policies!)

And now wait till the magic happens 🙂

Last but now least. When you change setting in the “configure automatic updates” policy you can trigger the client with powershell so you don’t have to reboot the client

gpupdate /force
net stop wuauserv
net start wuauserv
(new-object -Comobject Microsoft.Update.AutoUpdate).Detectnow()

You get get more information about Windows update log with the command.

Get-WindowsUpdateLog

Happy updating!

OK… Even with all the tips. Sometimes you need rename the software distribition folder also so I present to you: The PLZ GIVE ME ******* UPDATES NOW SCRIPT!!!! (runas admin)

gpupdate /force
Start-sleep -seconds 10
Stop-Service -Name BITS, wuauserv -Force
Remove-Item "$env:SystemRoot\SoftwareDistribution\" -Recurse -Force -ErrorAction SilentlyContinue
Start-Service -Name BITS, wuauserv
$updateSession = new-object -com "Microsoft.Update.Session"; $updates=$updateSession.CreateupdateSearcher().Search($criteria).Updates
Start-sleep -seconds 10
wuauclt /detectnow
wuauclt /reportnow
(New-Object -ComObject Microsoft.Update.AutoUpdate).DetectNow()

Move a window when you don’t have any focus

Method #1
Won’t work with a maximized Window.

  • Alt-Tab or Click On the Window
  • Press “Alt & Space”
  • Press “M”
  • Use your arrow keys to move the Window
  • Press Enter to exit

Method #2
Will move your Window to the right or left half of the screen in the same manner as dragging a window to the right or left of the screen will.

  • Press the Windows Key & Right Arrow or Left Arrow
  • Move a Window with the Keyboard-right

Method #3
will move your Window one display to the right or left.

  • Press the Windows Key & Shift & Right Arrow or Left Arrow

This is an copy paste from a website. All credits to: http://www.sevenforums.com/tutorials/77361-move-window-keyboard.html

Create a strong self-signed certificate for multiple years

If you follow these steps you can create a self signed certificate with the following specifications:

  • Wildcard certificate
  • SHA256 hash
  • 10 years
  • 2048 bits public key
  • Client and server verification
  • Sha1 fingerprint

Be aware that self-signed certificates can manipulate by a man-in-the-middle. You should not use this in critical production environments.

Please use windows 10 powershell in admin mode. Otherwise you will get errors

New-SelfSignedCertificate -certstorelocation cert:\localmachine\my -dnsname *.domain.local -NotBefore $([datetime]::now.AddDays(-15)) -NotAfter $([datetime]::now.AddDays(3560))

Now export the certificates. Before you copy/paste change the thumbprint with the thumbprint you get from the above command.

$CertPassword = ConvertTo-SecureString -String "YourPassword" -Force –AsPlainText
Export-PfxCertificate -Cert cert:\LocalMachine\My\C6B46CEB7D3A40DB08E78B19FEDD3A24EA7A7919  -FilePath C:\test.pfx -Password $CertPassword
Export-Certificate -Cert Cert:\LocalMachine\My\C6B46CEB7D3A40DB08E78B19FEDD3A24EA7A7919 -FilePath C:\tstcert.cer

Now you can import the PFX with IIS and bind the certificate in IIS.
And import the *.CER in your MMC > Certificates > Computer account > trusted root Certification authority > Certificates

Have fun with your certificate the next 10 years 😀

command-prompt-powershell

Inspiration

BSOD Domain Controller STOP: c00002e2 Directory Services could not start

Today our domain controller had a very bad day and had a bootloop after a reboot. I used recording software to capture the blue screen error: STOP: c00002e2 Directory Services could not start

Then we found a nice article to fix this issue. We had a second working domain controller so if you have the same setup you can use this how to, to fix this problem also. All the credits go to dbutch1976

  1. Restart the server and press F8 key, select Directory Services restore mode.
  2. Log in with the local administrator username and password (hope you remember what you set it to!).
  3. Type cd \windows\system32
  4. type NTDSUTIL
  5. type activate instance NTDS
  6. type files
  7. If you encounter an error stating that the Jet engine could not be initialized exit out of ntdsutil.
  8. type cd\
  9. type md backupad
  10. type cd \windows\ntds
  11. type copy ntds.dit c:\backupad
  12. type cd \windows\system32
  13. type esentutl /g c:\windows\ntds\ntds.dit
  14. This will perform an integrity check, (the results indicate that the jet database is corrupt)
  15. Type esentutl /p   c:\windows\ntds\ntds.dit
  16. Agree with the prompt
  17. type cd \windows\ntds
  18. type move *.log c:\backupad   (or just delete the log files)

This should complete the repair.  To verify that the repair has worked successfully:

  1. type cd \windows\system32
  2. type ntdsutil
  3. type activate instance ntds
  4. type files        (you should no longer get an error when you do this)
  5. type info       (file info should now appear correctly)

Source: https://social.technet.microsoft.com/Forums/windowsserver/en-US/771b97ad-4e1c-4e7c-8617-91601224dd7f/server-core-2008-r2-blue-screen?forum=winserverManagement

Windows IOPS and MB/s benchmarking

You have bought een new system and the first thing what you want to do is check the disk performance (ehhh that’s always the first thing I want to know 😛 )

There  is one tool I always use: ATTO Disk Benchmark

disk-benchmark

This is a very nice tool to quickly see how fast your troughput is of your new system.

But sometimes you want to check your IOPS. Then you can use another nice microsoft commandline benchmark tool DiskSpd

You can use this parameter to benchmark:

diskspd -b8K -d30 -o4 -t8 -h -r -w25 -L -Z1G -c20G testfile.dat

This example command line will run a 30 second random I/O test using a 20GB test file located on the T: drive, with a 25% write and 75% read ratio, with an 8K block size. It will use eight worker threads, each with four outstanding I/Os and a write entropy value seed of 1GB. It will save the results of the test to a text file called DiskSpeedResults.txt. This is a pretty good set of parameters for a SQL Server OLTP workload.

Example:

diskspd
Orginal article

If you get errors like:

Results for timespan 1:
*******************************************************************************
The test was interrupted before the measurements began. No results are displayed.
Error generating I/O requests

Or file creation errors like “Error opening file: testfile.dat” please try to replace the minus “-” characters with your keyboard. Sometimes your browser copy the wrong character.

Happy benchmarking 😀

Remove Windows 2008 r2 WinSXS “Windows Update” files

copy C:\Windows\winsxs\amd64_microsoft-windows-cleanmgr_31bf3856ad364e35_6.1.7600.16385_none_c9392808773cd7da\cleanmgr.exe to %systemroot%\System32

copy C:\Windows\winsxs\amd64_microsoft-windows-cleanmgr.resources_31bf3856ad364e35_6.1.7600.16385_en-us_b9cb6194b257cc63\cleanmgr.exe.mui to %systemroot%\System32\en-Us

Run cmd > cleanmgr and remove all the nasty update files!

After I cleaned up the server I had to stop the windows installer service (trustedinstaller.exe) to remove the c:\windows\logs\cbs\CBS.log (6GB file) manually. Maybe a restart of the server do the same but I cannot test it on a production environment.

Have fun!

Source: https://support.appliedi.net/kb/a110/how-to-enable-the-disk-cleanup-tool-on-windows-server-2008-r2.aspx