Aleksandar's computer workshop

Let's see what Aleksandar was fixing today.
My findings, tips & tricks related to computers, internet, programming and other stuff I was working with.

Terminal Service client not using saved credentials

When connecting via Remote Desktop to Windows 2008 server it always fails with the following message:

"Your credentials did not work. Your system administrator does not allow the use of saved credentials to log on to the remote computer because its identity is not fully verified. Please enter new credentials."

This error occurs only when I try to go from domain client computer to non-domain server.

In order to fix this you have to do following:

  1. Log on to your local machine as an administrator.
  2. Start Group Policy Editor - "gpedit.msc"
  3. Navigate to "Computer Configuration\Administrative Templates\System\Credentials Delegation".
  4. Double-click the "Allow Saved Credentials with NTLM-only Server Authentication" policy.
  5. Enable the policy and then click on the "Show" button to get to the server list.
  6. Add "TERMSRV/*" to the server list. You can also put their exact server name or for example to enable the setting on all servers in "" domain you can type "TERMSRV/*".
  7. Confirm the changes by clicking on the "OK" button until you return back to the main Group Policy Object Editor dialog.
  8. At a command prompt, run "gpupdate" to force the policy to be refreshed immediately on the local machine


Best way to practice and learn how to manage complex networks

Just use GNS3!

GNS3 is a graphical network simulator that allows simulation of complex networks.
To allow complete simulations, GNS3 is strongly linked with :

  • Dynamips, the core program that allows Cisco IOS emulation.
  • Dynagen, a text-based front-end for Dynamips.
  • Qemu, a generic and open source machine emulator and virtualizer.

GNS3 is an excellent complementary tool to real labs for network engineers, administrators and people wanting to pass certifications such as CCNA, CCNP, CCIP, CCIE, JNCIA, JNCIS, JNCIE.

It can also be used to experiment features of Cisco IOS, Juniper JunOS or to check configurations that need to be deployed later on real routers.

This project is an open source, free program that may be used on multiple operating systems, including Windows, Linux, and MacOS X.

Features overview

  • Design of high quality and complex network topologies.
  • Emulation of many Cisco IOS router platforms, IPS, PIX and ASA firewalls, JunOS.
  • Simulation of simple Ethernet, ATM and Frame Relay switches.
  • Connection of the simulated network to the real world!
  • Packet capture using Wireshark.

Some usefull links:

A lot of documentation and video tutorials

Download page


How to move Windows DNS Server zones to another Windows DNS server

If you are looking to transfer an entier DNS Server including Active Directory settings and things like that, you may better use DNSDump.cmd script from here:

Just to migrate the zones, simply do following:

1. On the DNS server that is currently hosting the DNS zone(s), change any Active Directory-integrated zones to standard primary. This action creates the zone files that are needed for the destination DNS server.
2. Stop the DNS Server service on both DNS servers.
3. Manually copy the entire contents (subfolders included) of the %SystemRoot%\System32\DNS folder from the source server to the destination server.
4. On the current (old, source) DNS server, start Registry Editor (Regedit.exe).
5. Locate and click the following registry subkey: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DNS\Zones
6. Export the Zones entry to a registry file.
7. Locate and click the following registry subkey: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\DNS Server\Zones
8. Export the Zones entry to a registry file.
9. On the destination (new) DNS server, double-click each registry file to import the Zones subkeys into the registry.
10. Bring the current DNS server down and transfer its IP address to the destination DNS server.
11. On the destination DNS server, start the DNS Server service. To initiate the registration of the server's A and PTR resource records, run the following command at a command prompt: ipconfig /registerdns
12. If this server is also a domain controller, stop and restart the Net Logon service to register the Service (SRV) records, or run the following command at a command prompt: netdiag /fix
13. The standard zones that were previously Active Directory-integrated can be converted back to Active Directory-integrated on the replacement DNS server if it is a domain controller.
14. Verify that the SOA resource records on each zone contains the correct name for the primary server and that the NS resource records for the zone(s) are correct.

inSSIDer is (much better) replacement for antient Netstumbler

inSSIDer is an free, award-winning Wi-Fi network scanner application for Windows Vista and Windows XP.
It scans networks within reach of your computer's Wi-Fi antenna, tracks signal strength over time, and determines their security settings (including whether or not they're password-protected).

NetStumbler, the most popular Wi-Fi network scanner, is free, but it hasn't been actively developed for years, and it doesn't work well with Vista or 64 bit OS.

inSSIDer, on the other hand, works like a charm on both Vista and XP, 32 and 64 bit, and it's open-source.

This must-have for hunting down Wi-Fi networks on the road.


  • Works with internal Wi-Fi radio
  • Wi-Fi network information (SSID, MAC, data rate, signal strength, security, etc)
  • Group by Mac Address, SSID, Channel, RSSI and "Time Last Seen."
  • Graph the strength of received signal in dBm over time
  • Filter access points in an easy to use format.
  • Highlight access points for areas with high Wi-Fi concentration.
  • Open source (Apache License, Version 2.0)