Eugene Siu's Thoughts on Security : Infoworker Productivity

Troubleshooting Networking and IPSec Issues

esiu — Mon, 05 Nov 2007 11:30:00 GMT

I had a very strange networking issue last weekend. After connecting to corpnet via VPN and direct hookup, I was able to ping all remote servers, but was not able to do anything, such as web browsing and remote desktop. It was not the first time that I faced this issue, and helpdesk told me that IPSec settings may have messed up.

The following set of commands has helped me flush settings related to networking and IPSec, and restored my corpnet connection in both situations.

1. Launch a DOS command prompt
2. netsh int ip reset all
3. netsh winsock reset
4. ipconfig /flushdns
5. nbtstat -RR
6. gpupdate /force

Akin to "Ctrl-Atl-Del" of your networking settings, this series of commands should flush IP interface, DNS, Winsock, NetBIOS and group policy settings.

Good luck to troubleshooting your networking and IPSec issues.

Read Office Files as ZIP

esiu — Fri, 19 Oct 2007 22:33:38 GMT

It is interesting to me that Office 2007 Metro formats can be broken down as a ZIP file. To see this in action, you can pick an Office 2007 Metro file, such as XLSX and DOCX, and rename its extension with ZIP. Then open the renamed file with WINZIP. You will see that Office 2007 content is laid out neatly in a ZIP. Check out this sample picture.

Let me illustrate a picture from http://www.devx.com/MicrosoftISV/Article/34934

View calendar via Date and Time Properties as non-admin

esiu — Fri, 11 Feb 2005 02:37:00 GMT

It is inconvenient that I cannot open Date and Time Properties as non-admin. Non-admins should not be able to change the date and time, but should be able to view it. Sometimes, I want to see what the date of next Wed is. Now I need to practice doing math in my brain if I run as non-admin. :)

Instead of using my rusty brain, I just grant myself "Change the System Time" privilege via Local Security Policy.
   1. Open Local Security Policy
   2. Go to Local Policies -> User Rights Assignment
   3. Double-click on "Change the system time"
   4. Follow the GUI to add myself to the privilege

How to enable Remote Desktop for non-admin?

esiu — Wed, 26 Jan 2005 08:56:00 GMT

After hearing from many that Power Users are still admin, I have converted myself to a regular user. Most apps continue to work properly. Remote Desktop stops working. To be specific, from the non-admin box, I can remote desktop to another machine, but not vice versa.

After fiddling with some settings, I discovered that regulars users are not enabled to remote desktop by default. After adding myself as a Remote User in the System Properties, I can start a Remote Desktop session to my box again.

Running as non-admin is not as hard as I imagine

esiu — Wed, 19 Jan 2005 19:51:00 GMT

As a security tester, we need to ensure that our product works under minimal privilege. Yes, test machines are set up to test with minimal privilege, but my day-to-day email machine is set up with admin privilege. Although it is a threat to run under admin, it was more threatening to inflict myself with the hassles of running as non-admin. As an extremely paranoid person, I have so many novice questions: Do I need to reboot all the time if I need admin privilege? Will my apps continue to function properly? Will I get blue screen for no reasons?

One fine day, I decided to switch from admin to power user. Granted that power user is almost an admin, it should be a good start to run my box as non-admin. After several days, I did not find any differences with Office applications and other well-known ones, such as IE.

Until I need to unblock an application on my SP2 firewall do I have a problem. The problem can easily be circumvented by using "runas /user:mymachine\administrator control firewall.cpl" and enter my password. After the command, I run firewall.cpl as admin, and unblock my application. Finally, close the firewall app.

Voila, I am happy again with running my box as non-admin.

Why is a JPG file forced to be saved as BMP in IE?

esiu — Wed, 29 Dec 2004 18:55:00 GMT

When I right clicked on IE 6 to save a JPG file, Save Picture dialog box only shows BMP as the only output format. It only reproes on some computers.

After some digging, I found out that Internet cache is full on the dubious computer. For more info, please check http://support.microsoft.com/default.aspx?scid=kb;EN-US;q260650