Using google authenticator with OpenBSD SSH logins
Introduction on two factor authentication Please read the following information on two factor authentication and why you would want to use it. http://en.wikipedia.org/wiki/Two-step_verification
NOTE: Make sure you leave a terminal with root access if you are using a remote system until you have tested that you can indeed authenticate to it!
Steps tested on OpenBSD 5.4, used tools on EL6 client to generate QR code. I’m mainly documenting this here so I can remember how to do this again.
Buffer bloat mitigation with OpenBSD pf
For an introduction to buffer bloat read more here http://en.wikipedia.org/wiki/Bufferbloat . My home network utilizes OpenBSD and the built in packet filter (pf). I use cable for broadband internet and found that if I tried to upload a large file my internet connecting became very unable with high amounts of latency. After utilizing tools such as http://netalyzr.icsi.berkeley.edu/blog/ it became obvious that I was suffering from buffer bloat. After doing some searching I came across using altq support in pf to try some configuration changes to reduce the buffer bloat in my configuration.
Orchestrating Your Storage: libStorageMgmt
NOTE: Updated 4/2/2015 to reflect new project links and updated command line syntax.
Abstract This paper discusses some of the advanced features that can be used in modern storage subsystems to improve IT work flows. Being able to manage storage whether it be direct attached, storage area network (SAN) or networked file system is vital. The ability to manage different vendor solutions consistently using the same tools opens a new range of storage related solutions.
There is suppose to be hot water in the water heater, right?
A local contractor installed a new furnace and water heater for me on 1/21/2013. The install appeared to go well. The furnace is keeping our house warm and the water heater runs without making crazy noise and it is producing hot water. All is perfect in the world, well not quite…
While checking out the water heater (AO Smith GDHE-50) I noticed that the lower side connect was quite cold, the brass drain was very cold too.
Fool me once, shame on you, fool me twice …
American water heater company, the maker of the water heater I installed issued me a return authorization number for the water heater that would not run when installed per the instructions. I installed the new one (1/5/2013) and this one works better (it will start), but still not great. It makes noise when starting and the flame is quite yellow and has bad shape. I have posted videos of the start and flame for technical support to look at.
I didn't do anything wrong
Ben, a plumber from K&S came by and spent 3 hours going over my install and inspecting the water heater. He found nothing wrong with my install, whew! After talking to technical support we got the unit running by removing the intake and restricting the exhaust. We had hot water, but the install wasn’t going to pass code as it deviated from the installation instructions.
Water heaters go virtually unnoticed, that is until they don’t work!
You shall not heat!
As I was unable to correct the negative pressure causing my atmospherically vented natural gas water to back draft at start, I decided to replace it. The 15 year old AO Smith 40 gallon, 40K BTU water heater had absolutely no issues, except that it left our house hold yearning for more hot water.
Obviously a new atmospheric vented water heater was out as it would exhibit the same problem as the old one.
We need some air in here!
In a previous posting I mentioned running into an issue with our water heater failing to draft when all the exhaust fans and clothes dryer running. I did some research and through testing I thought the entire issue could be resolved by adding more “make-up air”. Thus I added a 6″ duct into our mechanical room. This was in addition to our existing 5″. You would think that after having ~48″ sq.
The pitfalls of making your home energy efficient
Over Thanksgiving I discovered a torrent of cold air pouring behind our shower in the basement and tracked it to a large opening in our attic. That same day I went and picked up some additional insulation and proceeded to close the opening. Problem solved right? Nope, instead I found out by sealing this rather large hole I made our home too tight. The problem is that in worst case testing (all exhaust fans running and the clothes dryer) a significant enough negative pressure was created which prevented our water heater from drafting correctly.