Objective

The objective is to mount a CD/DVD block device with ISO 9660 disk image/media.

Requirements

Privileged access to your Redhat 7 system.

Difficulty

EASY

Conventions

  • # - requires given linux commands to be executed with root privileges either directly as a root user or by use of sudo command
  • $ - requires given linux commands to be executed as a regular non-privileged user

Instructions

Locate Block device

First we need to find a correct CD/DVD block device. To do this execute a command blkid:
# blkid
/dev/xvda1: UUID="b4f59ae4-f5c8-49c2-94cf-103e10eef407" TYPE="xfs" 
/dev/xvda2: UUID="zcwKzx-w2EM-NH4E-wQW3-7QTu-62JZ-s6Ok0j" TYPE="LVM2_member" 
/dev/sr0: UUID="2016-10-19-18-32-06-00" LABEL="RHEL-7.3 Server.x86_64" TYPE="iso9660" PTTYPE="dos" 
/dev/mapper/rhel-root: UUID="ea637699-1d70-49ef-9a0a-54bc87d1e571" TYPE="xfs" 
/dev/mapper/rhel-swap: UUID="617ccf82-602c-472d-bff6-484d95530293" TYPE="swap" 

Objective

Resetting the root password in RHEL7/CentOS7/Scientific Linux 7

Requirements

RHEL7 / CentOS7 / Scientific Linux 7

Difficulty

MODERATE

Instructions

Things have changed in the RHEL7 world and so has the preferred way of resetting the root password. Although the old way of interrupting the boot process (init=/bin/bash) still works, it is no longer bulletproof and recommended. 'Systemd' uses 'rd.break' to interrupt the boot. Let's have a quick walk through the whole procedure.

Introduction

If your Redhat server is not connected to the official RHN repositories, you will need to configure your own private repository which you can later use to install packages. The procedure of creating a Redhat repository is quite simple task. In this article we will show you how to create a local file Redhat repository as well as remote HTTP repository.

Using Official Redhat DVD as repository

After default installation and without registering your server to official RHN repositories your are left without any chance to install new packages from redhat repository as your repository list will show 0 entries:

# yum repolist
Loaded plugins: product-id, refresh-packagekit, security, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
repolist: 0

This guide will discuss a procedure on how to connect/establish a VPN connection using PPTP protocol on CentOS 7 or Redhat 7 Linux the non-GUI way. Below you can find connection details which will be used as an example. Replace the bellow PPTP VPN information to align with your PPTP VPN server settings:
  • Connection name: linuxconfig ( can be any descriptive name )
  • VPN connetion type: PPTP
  • PPTP VPN server IP or domain: 123.123.1.1
  • CHAP Username: admin
  • CHAP User password: 00000000

Configuration

Let's begin by installation of PPTP client:
# yum install pptp

This config will describe a procedure on how to persistently load kernel modules during a boot time on CentOS or Redhat Linux system. In the below commands will use nf_conntrack_pptp as a sample module. Replace the name of this module with a module name you wish to load.

First, create a script within /etc/sysconfig/modules/ directory with a file extension modules. Where the name of the script can be any name of your choice. In our case the script will be called nf_conntrack_pptp.modules. Enter a following code into your new nf_conntrack_pptp.modules script while replacing the name of the module with the one you wish to load:
#!/bin/sh
exec /sbin/modprobe nf_conntrack_pptp  >/dev/null 2>&1

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