“How the Internet Works” is the name of my new unit for the freshman classes. I’m just trying to give a general overview. Today I introduced IP addresses, domain names, and DNS. I designed an activity using nslookup to inspect DNS records of common domains and look up domain names from IPs. Then, students will use the numeric IPs to access web sites and see that the mapping between domain and IP is not always as direct as it seems.
The only problem is that when the students log in, the command prompt is disabled in Windows. I guess this is supposed to enhance security or something. Anyway, I had to scramble this morning to find a DNS/reverse-DNS lookup utility thats free, doesn’t require administrative privileges to install (and preferably doesn’t need to be installed), and can do both forward and reverse DNS lookups. So far, I haven’t succeeded. The best I could do was dnsquery.
Any suggestions? This is turning out to be a lesson in how Windows gets locked down, instead of how the internet works. Or maybe this actually is how the internet always works. I wasn’t trying to be ironic, I swear!
Posted by dsakima on September 10, 2007 at 10:58 am
Hey Ben!
Here’s a web based DNS look up, is that kinda what you were looking for?
http://www.zoneedit.com/lookup.html
I’m glad your teaching this stuff, I’m afraid this is how kids see the Internet:
1. Click blue E
2. Search for ‘www.myspace.com’
3. Click on the first search result for ‘www.myspace.com’
Posted by Ben Chun on September 10, 2007 at 11:45 am
I was hoping to avoid using a web-based tool because I wanted them to see that their computer can (and has to) do DNS lookups for itself. But if I can’t find a decent little utility, and we’re locked out of the command line, perhaps a web interface is the best way to do it.
I kinda like the simplicity of http://www.ipchecking.com
Posted by Computer Science Teacher - Thoughts and Information from Alfred Thompson : Department of Learning Prevention on September 10, 2007 at 4:05 pm
[...] Ben Chun reports in his blog how his attempt to demonstrate how DNS works to translate domain names to IP addresses was foiled by the fact that his students are locked out of the command prompt. This is a pretty typical lock down I have found. Anyone know “a DNS/reverse-DNS lookup utility that is free, doesn’t require administrative privileges to install (and preferably doesn’t need to be installed), and can do both forward and reverse DNS lookups.” If so drop by his blog and leave him a comment. [...]
Posted by Ben Chun on September 10, 2007 at 9:06 pm
And the winner is… PriaSoft NSLookup!
http://www.priasoft.freeserve.co.uk/nslookup.html
Posted by Ben Chun on September 11, 2007 at 8:27 am
I spoke too soon: PriaSoft NSLookup crashes under Windows 2000 (but not XP) when trying to do a lookup by address. Sigh.
Posted by Sal M on September 11, 2007 at 3:39 pm
Sir, How about http://www.sb-software.com/dnsquery/ .
Posted by Sal M on September 11, 2007 at 3:42 pm
http://www.21century-ecommerce.com/dnsr_revdns.htm has one as well.
Posted by Ben Chun on September 12, 2007 at 10:19 am
Thanks for those links, Sal. I’m tempted to write my own GUI wrapper for nslookup. Who knew that teaching high school would actually lead back around to Windows programming? I thought I had escaped!
Posted by Email Headers « And Yet It Moves on September 13, 2007 at 11:03 am
[...] has an IP address. They figured out forward and reverse DNS lookups, although we did run into some problems when students didn’t have permission to open the command prompt and run nslookup. But I [...]