Friday, April 20, 2007

Simple whitelist Internet filter

How to limit access to Internet websites so that only specified websites are allowed?

If you have a Linux machine available, you can use squid to setup a whitelist. This is a very effective and easily setup.

Modify squid's /etc/squid.conf as follows:


acl white dstdomain "/etc/squid/whitelist"
http_access deny !white


Create the /etc/squid/whitelist file and add domain names like .pcastl.org one per line.

Setup your router to only allow your Linux box access to the Internet. This is normally done my adding a allow list of MAC addresses. Then configure all other machines on your network to point to the Linux box as there web proxy.

See the following link for detail instructions about setting up the proxy. Note if all you want is a whitelist then you don't need SquidGuard. Also note the config lines in this article are incorrect. Use the ones I show above.

If you want your other machines to be able to access email then use rinetd to redirect some port on the Linux box to your mail server and setup all other machines on the network to point to the Linux box as their mail server. You could alternatively setup iptables rules, but rinetd is much simpler to setup.

Thursday, April 19, 2007

Move to Pensacola, FL

As announced today on the company internal 'The OCI/Advantage Business Summary':

Kevin Heifner is planning on moving his family to Pensacola, Florida in the third quarter of this year. The move was promoted by family desires related to his children attending a specialized school. Kevin will continue to support OCI from Florida.

Sunday, April 08, 2007

5 Things About Myself

I was blog tagged by Weiqi Gao. I'm not really sure what that means, but I will follow the lead of others and tell 5 things that you probably don't know about me.

1. I think I was a freshman in high school when I built a bomb that almost killed me. Actually it was suppose to be a rocket, but it didn't quite go as planned. I took an empty CO2 cartridge (the kind used for beebee guns) and stuffed it full of match heads. I put the CO2 cartridge in a PVC pipe and lit it. I'm fortunate that it was a very cold day and I had many layers of clothes on. My clothes were full of holes and it is only the grace of God that kept me from killing myself. Only one piece of PVC pipe made it into my right arm. I still have the scar from where they cut it out. Also the side of my folks garage siding is still perforated with holes.

2. In my small high school (graduating class of 50) I was the school high jumper in track-n-field. My personal best was 5'10" which was over my height of 5'8". I also participated in a school record in the 440 yard relay.

3. I wouldn't say I'm a big music fan. I own very few CDs. Normally I listen to classical while driving. However, I do like the band Third Day.

4. My first computer was an Apple II+ my dad bought when I was in grade school. I thaught myself to program Apple Basic by listening to tapes that came with the computer.

5. Many of you know that I'm a 'born again Christian'. I align myself with the Reformed Christian faith. One of my favorite books is: The Reformed Doctrine of Predestination by Loraine Boettner.

Friday, April 06, 2007

Iridium One of 21 Biggest Technology Flops

For those who worked on the Iridium project, you may find it interesting that Iridium made ComputerWorld's list of 21 Biggest Technology Flops.

Wednesday, February 28, 2007

int to String under Managed C++

I have been doing a little managed C++ at work the last couple of days. Did you know you could do this:

System::String^ str = gcnew System::String("");
str += 5;
System::Console::WriteLine(str); // prints: 5

or simply:

System::String^ str = "";
str += 5;
System::Console::WriteLine(str); // prints: 5

or even:

System::String^ str;
str += 5;
System::Console::WriteLine(str); // prints: 5

The 5 is converted to a String for you. After working with C++ for so many years without a simple way to convert an int to a string this is nice. Might not seem like that big a deal, but these little things add up.

CityDesk on Vista

I use CityDesk to maintain my kid's school website: Providence Christian Academy. It would not run under Vista because it needed the DHTML Editing Control. However, a quick download and install and I was up and running again.

Firefox on Vista

As some of you know, I have started using Windows Vista Business on my work laptop. I received a free version for participating in Power Together campaign. I prefer Firefox to IE, even IE7, so I wanted to make it the default browser on Vista. I looked around and it appears that many people are having problems getting this to work. Here is what I did:

- Run Firefox as Administrator by right-clicking on the icon in the Quick Launch Toolbar.
- Select Tools->Options->MainTab
- Click "Check Now" button under System Defaults.
- Indicate you want Firefox as the default browser.
- Close Firefox (remember you are running as Administrator.

Works great.