CentOS/RHEL

The Problem Unable to generate kdump and fails with the following error: Checking for memory holes : [100.0 %] | copy_bitmap_file: Can’t write the bitmap(/tmp/kdump_bitmapQijuck). No space left on device” kdump: dump target is /dev/[ 14.793505] EXT4-fs (dm-0): re-mounted. Opts: (null) mapper/VGExaDb-kdump_vol kdump: saving to /kdumproot/kdump/u01/crashfiles/127.0.0.1-2020-04-29-09:46:31/ kdump: saving vmcore-dmesg.txt kdump: saving vmcore-dmesg.txt complete kdump: saving […]

sudo will normally only log the command it explicitly runs. If a user runs a command such as sudo su or sudo sh, subsequent commands run from that shell are not subject to sudo’s security policy. The same is true for commands that offer shell escapes (including most editors). If I/O logging is enabled, subsequent […]

Restricted bash shell can be invoked using below command: # bash -r The ‘/bin/rbash‘ represents the restricted bash shell and can be created by creating as a soft link to ‘/bin/bash’ as shown below: # ln -s /bin/bash /bin/rbash Once soft link for /bin/rbash is created, one can launch restricted bash shell using below command: […]

How to generate PGP keys using GPG on Linux The GNU Privacy Guard application allows you to encrypt and decrypt information, create public and private encryption keys, and use or verify digital signatures. GPG is based on the use of a pair of keys, one public and one private (or “secret”). Data encrypted with one […]

This post describes how to identify Network Information Service (NIS) authenticated users. 1. To obtain a complete list of all NIS users, run the ypcat passwd command For example: [root@nisserver ~]# ypcat passwd test2:x:504:504::/home/test2:/bin/bash user1:x:501:501::/home/user1:/bin/bash user2:x:502:502::/home/user2:/bin/bash user3:x:503:503::/home/user3:/bin/bash 2. To identify whether a specific user is a NIS user, run the ypmatch [username] passwd command. – […]