Category: Linux and UNIX

The big cybersecurity news of the past couple of weeks has been the WannaCry worm. It took advantage of some rather old bugs, dating back to Windows XP and Windows Server 2003. We got lucky! The vulnerability, the problems in the targets, allowed unlimited abuse. But the exploit, the attackers’ code, had a built-in “kill […]

Perfect is the enemy of good. That’s an old saying. Confucius (551-479 BC) said, “Better a diamond with a flaw than a pebble without.” Aristotle (384-322 BC) said something similar. Voltaire popularized the phrase in the 1770s. And maybe that’s where we are with SDN WAN. Software-Defined Networking and Wide Area Network Links Software-defined networking, […]

Do you know how to check the IP address of a Linux server? “Of course!”, you say, and you type this: $ ifconfig eth0 Not anymore! Both the command ifconfig and the interface name eth0 have been obsolete for a few years now. However, many organizations still use something like Red Hat Enterprise Linux 6, […]

Recently, I posted about basic permissions for Linux files; now let’s look at how to access those in a shell script. Testing file permissions is an essential part of enforcing an access control policy. Two common ways to test files for readability, writability, zero size and so forth are the if and the test. For […]

Red Hat Linux won’t play MP3 audio or MPEG video files. This isn’t a new issue. Red Hat removed the codecs, the encoding and decoding shared libraries, back in September 2002 when Red Hat 8 came out. For the first five years they provided an explanation, you can still find it at archive.org. The decision […]