Archive for December, 2010

The easiest way to test the memory in your Intel-based PC!

Most admins have a series of tools they use to check for faulty hardware. This toolkit most likely includes the ultimate boot disk, a network accessible memtest and preclear_disk.sh on a USB stick. I was always curious why Linux disitrubtions didn’t integrate these items into their install / live CDs, since it would make debugging […]

Forcing your Linux users to use strong passwords

All SysAdmins know the importance of using strong passwords. These are the life blood of our systems, since a weak password will allow an adversary to enter our systems with a minimal amount of work. There are dozens of tools that can generate strong passwords, as well as a number of tools that can be […]

Finding approximate matches in a data file with agrep

A few weeks back I ran into a situation that required me to locate a data given a file with various variations of that data. I proceeded to grep for each form of the string (e.g., “teh”, “the”, “tte”) I could think of, but wasn’t getting the results I wanted. After a bit of poking […]

Making sense of the various routing / firewall solutions that are available

I am currently running dd-wrt at home. Dd-wrt works pretty well, but I recently started to do some digging to see what other routing / firewall solutions existed. There are a bunch of routing / firewall gateway solutions available, and each one provides a unique experience. Some run on Linux, some on OpenBSD, and others […]

Locating the SSH key type and key size from a public key file

One of my friends sent me an e-mail earlier this week inquiring about SSH keys. Specifically, he wanted to know how he could determine the type of key and the key-size in a public key file. All openssh implementations ship with the ssh-keygen utility, which has a “-l” option that can be used to print […]