My Little Pocket Universe
Posts about linux in general that are not tied to a specific distro.
It seems like everywhere you log in these days wants you to use some kind of 2 factor (multi-factor) authentication. The most common one you will have likely seen is the OATH time based code generation where you use an authenticator app to generate codes that cycle every 30 seconds. Well, it turns out you … Read more
Sometimes you need a way to get in to a system that is not accessible publicly, and for whatever reason, you can’t use a full VPN. This is a good time for the connectivity Swiss-Army-Knife, and your best friend, ssh and, if available, its companion autossh. And for you Windows people, I mean ssh, not … Read more
Sometimes you will end up with a linux host that is swapping, and many times it will be obvious which process has been chewing up swap (hint: it is always java). But in those cases where it is not as apparent, I whipped up a little bash script to walk the process tree and list … Read more
Linux has great facilities to view what is happening with the hardware and kernel, but the information isn’t always in one place or organized for humans to look at. Seeing the fibre channel HBAs and the attached devices is a prime example. Getting a quick view is a royal pain. Here is a bash script … Read more
To add an extra layer of security to your server, especially when you are working on a shared client, you can add SSHFP records to the DNS record of the host. This allows the ssh client to pull the hash of the server from DNS to add an extra layer of verification that the host … Read more
If you have the HashKnownHosts option for your ssh client set to yes, then you have a more secure known_hosts file so that a bad actor cannot easily get a list of the hosts you connect to, which is a good idea. However, it also hides it from you, so if you need to remove … Read more
While I was updating some settings with my bind server on Ubuntu 20, I noticed a lot of queries for “pizzaseo.com”, which appears to be some kind of marketing company trying to scrape for data. On reading out in forums about it, apparently they’re looking for vulnerable pi-hole servers that are exposed to the internet. … Read more
I was looking for a way to compare compression ratios with different algorithms, and didn’t want to have to run them in serial. So I started digging and found a nice bash syntax that allows you to do just that. And just for fun, it calculates the sha checksum as well. curl -s https://someserver.com/file.txt | … Read more
A while back, I found a nice TrueType font that mimicked the old DEC terminals. It was made by taking the ROMs of a DEC VT220, and creating the TTF font based on that data. It occurred to me that it would also make a really great replacement for the linux console font, where it … Read more
Sometimes it’s desirable to have a back door into a system that is behind a firewall. ssh is a security person’s best friend, and worst nightmare. This is more in the latter category, but as an admin, incredibly useful. I have a server that I can get outbound connections to anywhere, but do not have … Read more