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SilverFir.net IP Change

For the first time since getting the cable modem installed, my IP address changed. The result was an extremely unreachable host.
With me in Portland with the Titan Robotics Club for the FIRST Robotics Competition, figuring out what exactly the problem was, then fixing it, was not a trvial task. Fortunately for me and for anyone else using SilverFir.net, my wonderful mother was local to the server and after restarting the server to no avail, she was able to confirm that it was indeed the IP address that had changed. A quick trip over to No-IP.com and I had the DNS switched over (changes go active worldwide in under 5 minutes!), but then there seemed to be a few latent problems. Apache didn’t start properly, leading me to expect that the server was still down. But then later, when I impulsively checked my email, and found that my mail server was working just find, I thought, “Wait a moment now…” An SSH session proved fruitful as well, and a quick reboot saw SilverFir.net back to full potential in under a minute. Just Lovely.

Useful Linux Command

Today I was searching for a good way to change permissions recursively, but only on directories or only on files, because of the vast difference in meaning for the executable flag between the two. Google is a great friend, and led me to a site, whose address I do not exactly remember, but whose advice was perfect:

find . -type d -name public_html -exec chmod 0755 {} \;

Just strip out the -name argument, and change between -type d and -type f to chmod only files or only directories, recursively from the current directory. A great way to correct past misconceptions about the setgid and setuid bits!

Good Reads on the Unix Security Scheme

The more I learn about the Unix security system, the more amazed I am with how well it accomplishes so many taks while remaining very lightweight with just 12 bits of permissions per file. With my newfound better understanding of the setuid and setgid bits, specifically at how they behave differently when applied to directories and files, I am now starting to think I have a pretty good grasp of how the Unix security scheme works, and how to make it both high security and highly usable. User Private Groups is in my view the best way to set up a user-friendly filesystem that allows for higher-than-average security and higher-than-average usability for webmasters.

CFML troubles

The website of the Titan Robotics Club uses the ColdFusion Meta Language (CFML) to generate and display its dynamic content. I posted earlier about how ColdFusion was an easy language to learn, and that it seemed semantically powerful, able to accomplish a lot in not too many lines of code. While that is still true, there seems to be a dark side to the ColdFusion story or at least that of our current host, readyhosting.com. It seems that of the server’s stability leaves something to be desired, especially on start-up. For example, if you are te first person to visit the site after some period of time and (at least this is what I speculate happens) the ColdFusion interpreter has shut down, you are greeted by a hideous page with SQL statements and unprocessed cfoutput statements, which is hopelessly ugly. Occasionally when just reloading the home page, you will witness the same phenomenon. Needless to say, we can only hope this doesn’t happen when a judge is around. So, to hopefully minimize the chance of this happening, I created a shell script that, every 30 seconds, reloads the home page, and logs whether it recieved a “big” (correct) or a “small” (incorrect) version of the page. This way, the command interpreter should remain active (hopefully) and I’ll get statistics on how often the page loads incorrectly, even after a “hot” start. Nothing like hard data with which to confront your host (or should it be Macromedia?) .
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Blue

While looking at my site today, I realized that it is way too blue. I’m gonna have to do something about that. But, as the procrastinator’s creed goes, why do something today that you can do just as easily tomorrow?

WordPress 1.5 – or not

I almost upgraded to WordPress 1.5 today, at the sugestion of Erik. Unfortunately, too much has changed to make transition a simple process, so I quikly backtracked almost all the way – I ended up with 1.2.1, 0.0.1 larger than I had before.

Trackback Spamming beginning to work

A little while back, I noticed that I was beginning to get some trackback spam. At the time, I thought it odd that the trackbacks didn’t actually show up as comments – yet I recieved the email as if they had been posted. It truns out that, beause the initial trackbacks I was getting were from poker places, they had in fact gone into the moderation queue (although WordPress did not inform me on this). Secondly, the spammers seem to have refined their techniques, as a couple of trackback comment spams actually made their way into comments on the blog. They have of course been utterly eradicated, long before google or even msn bots could have picked them up, but now I have to make a decision between learning how trackbacks work so I can implement some sort of more intellegent anti-trackback-spam scheme, or simply disabling trackbacks altgether. I don’t want to have to resort to the later techniques, but real trackbacks are not all that common for me, so its not out of the question.