David Trebacz Blog

I was very pleased when Dreamhost built in free security certificates from the Let's Encrypt service. Here's a the Dreamhost and Let's Encrypt integration announcement . Unfortunately, utilizing this meant you couldn't use the cloudflare service without upgrading. I decided to roll my own CDN to speed up my brother's stain glass shop's website . The page load speed dropped by almost 200% and site site feels speedy when browsing now. After researching many solutions and option I settled on this solution. I didn't want using a CDN to exclude or confuse anyone (or any search engines) looking for our content. The CDN I created is all under our primary domain with canonicals pointing back to the original content to avoid any accidental duplicate content penalties by search engines. I created  3 secure CDN sub-domains and choose the free Let's Encrypt SSL certificate in Dreamhost hosting console to serve up our images, fonts, css and js. https://cdn.gl

I moved to Phoenix/Scottsdale Arizona area a couple years ago from the midwest and found a whole new group of creatures. The one that bothered my wife the most was scorpions. The day we moved into our house we found one lonely scorpion limping alone the baseboard in our living room. She freaked out a bit and I went to the internet to find a Do It Yourself (DIY) way to kill scorpions. Online I also found out that Arizona is home to the pretty nasty bark scorpions. First we bought a LED UV flashlight so we could easily see them. We used it to find scorpions at night and figure out where they may hide or nest nearby. It also was a fun "hunting" exercise for our nephews. Thankfully we only found a few scorpions on our property and weren't infested. LED UV Flashlight   Ultraviolet Black Light Flashlight  - Inexpensive aluminum LED UV flashlight from Amazon. Just remember to by the 3AAA batteries for it. Backpack Sprayer   Chapin 61800 4-Gallon ProSeries Backpack Sprayer

It seems Honeywell added some new features with a recent update to the RTH9580WF WiFi thermostat firmware. One new feature is called Utility Schedule Options. I looked on their website and found no information on it, so I decided to put together this blog post and a Utility Schedule tutorial video . The feature allows people to take advantage of special time of day pricing programs offered by Electric utility companies. I did this in the past by setting up my schedule, but essentially lost 2 programs steps setting it up. The new menu item is under "preferences" under main "menu" (Menu>Preferences>Utility Schedule Options>On). Video tutorial of Utility Schedule option setup The video walk though of RTH9580WF Utility Schedule options setup , I shot walks through the setup. It also gives an idea of the different options you can set (up to 4 different breaks and active on different days). The thermostats then uses the temperature limits you set on

I'm still having issues with the Honeywell wifi thermostat (RTH9580WF) displaying "waiting for update" on when the wifi is routed through my proxy server, so I decided to do a deep dive into what the thermostat is doing when it's getting the weather updates. I also wanted to better understand how to trace traffic on my network. Here's what I learned about the thermostats weather updates system by tracing the communication between the thermostat and servers. Currently: Thermostat requests the current weather and 12 hour forecast from a server:  http://104.209.185.251 . This server appears to run code managed by Honeywell in Microsoft's Azure cloud. Every 15 minutes it makes two port 80 GET requests to the IP address: http://104.209.185.251/WeatherAPIProd/api/weather/current?appKey=b9db7a3d469892e8&language=en-us&locationKey=36691_PC  (return current weather for location) http://104.209.185.251//WeatherAPIProd/api/weather/forecasts/hourly/12hou

I was noticing that many of the Arpwatch notification messages coming back were marked "unknown" for the manufacturer name in the MAC address lookup. I looked at the date of the file in my Ubuntu file system and it was last updated in 2012. Arpwatch uses this file to determine the manufacturer name for a given MAC address prefix. I found a script at this blog post which looked quite promising. A few simple transformations of the file downloaded direct from IEEE, updates from the comments on the blogpost and it was ready to go. I added in the lines to copy the files to the correct locations in Ubuntu's implementation of Arpwatch. Here is the updated script: Here are the basic steps and commands to do it on a terminal session. 1.Create the script using nano (copy and paste the script above) into a file called update_mac_addresses and then run it. nano ~/update_mac_addresses.sh 2. Make it executable chmod +x ~/update_mac_addresses.sh 3. Execute the script. S

I found a quick and easy way to setup a way to test network speed on my internal network using the linux command line tool netcat (or nc), I used this for node to node testing of my wireless network under a variety of conditions. It required no extra tools or software to be installed on my Ubuntu linux machines. It gives me transmit speeds I can understand and easily allows me to size the payload to the type of network I'm testing. Put the first machine in listening mode (this example machine 192.168.0.188): nc -lk 2112 >/dev/null Put the second machine in transmit mode to send packets to first machine 192.168.0.188: dd if=/dev/zero bs=16000 count=6250 | nc -v 192.168.0.188 2112 The first part of the command tells the machine to copy 100 MB of data from /dev/zero in 16 KB blocks. The part after the pipe tells it to send that to the first machine (192.168.0.188) over port 2112. The output for this test on the second machine returns: Connection to 192.168.0.188 2112