The purpose of /etc/networks

The purpose of /etc/networks Also wondering what particular files do on Linux? One of those files we recently rediscovered during auditing is the /etc/networks file. For some reason it was always there, yet we never change it. When looking at the man page of networks(5) we learn its purpose (almost instantly): It translates between IP ranges and network names It is used for tools like netstat and route It only works on class A, B, or C networks It does […]

Read more

Linux system hardening: adding hidepid to /proc

Hiding processes for other users The pseudo-filesystem /proc contains a lot of useful information for the system administrator. It also shares a lot to normal users on the system. We can change what can be seen by using the right mount options. When looking in /proc you will discover a lot of files and directories. A lot of these directories are just numbers and represent the information about a particular process ID (PID). By default, Linux systems are deployed to allow […]

Read more

Linux History: How Dot Files Became Hidden Files

History of Hidden Files Ever wondered why there are files on your Linux system, starting with a dot? The short answer: they are shortcuts. The story begins many years ago, when the first file systems were created on UNIX. To allow easy navigation, a single file with a dot (.) was added in each directory. Secondly a double dot file (..) was added to easily move up in the directory structure. As these files had no real data in them, […]

Read more

Using xattrs or Extended Attributes on Linux

Using xattrs or Extended Attributes on Linux Extended attributes, xattrs for short, are an extensible mechanism to store metadata along files. In other words, they describe some additional properties of the file. Normally this information is limited, like ownership and dates. With xattrs more information can be stored about the file. Support for xattrs Not all file systems have support for xattrs, but nowadays the most common ones support it (EXT4, Btrfs, ReiserFS, JFS and ZFS). To determine if your […]

Read more