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Viewing articles tagged 'centos'

 /etc/rsyslog.conf – Setup a Filter to Discard or Redirect Messages

The post outlines steps to create a Property-Based Filter to Discard( suppress ) a particular...

 3 Ways to List All Installed Packages in RHEL, CentOS and Fedora

To list all installed rpm packages on CentOS, RHEL and Fedora distributions using four different...

 How to add a custom script to the systemd in CentOS/RHEL 7?

The systemd facility replaces the older System-V initialization scripts from earlier releases....

 How to Change Default Permission of /var/log/messages in CentOS/RHEL?

By default, /var/log/messages* are created with read-write permissions for ‘root’ user only....

 How to change the Default Log Directory(/var/log) in Rsyslog for CentOS/RHEL 6,7?

The default location of /var/log/messages file can be changed to any location of your choice....

 How to change the default permissions of log files created by rsyslog?

The user wants to change the default permissions of the log file /var/log/messages to make it...

 How to Change Time Interval to Fall Back to Secondary DNS Server in CentOS/RHEL?

The parameter timeout:n can be set in the configuration file /etc/resolv.conf to adjust the time...

 How to configure chrony statistics in CentOS / RHEL 7?

The chronyd service uses the /etc/chrony.conf configuration file to set synchronization...

 How to configure encrypted swap using LUKS in CentOS/RHEL?

In environments such as government companies, users may want to secure their data which can...

 How to configure interface in “Promiscuous Mode” in CentOS/RHEL?

Promiscuous mode or promisc mode is a feature that makes the ethernet card pass all traffic it...

 How to Configure Interface(s) in promiscuous mode on CentOS/RHEL 7 (persistently)?

Promiscuous mode or promisc mode is a feature that makes the ethernet card pass all traffic it...

 How to Configure Network Teaming in CentOS/RHEL 7?

In earlier versions of RHEL, network bonding was the default method for creating aggregated...

 How to Configure rsyslog to Filter/discard Specific IP Address in CentOS/RHEL 6,7?

Follow below steps to configure rsyslog to filter messages with specific IP address.   1....

 How to configure rsysnc in daemon mode (allow rsync and disable SSH login) in CentOS/RHEL?

To allow rsync and disable ssh by configuring rsync in daemon mode. In order to achieve this...

 How to Configure UDEV rule to allow read-only permissions on USB devices?

Following steps to configure udev rule which would automatically switch the USB disks to...

 How to connect to an Active Directory Domain using Realmd (Configure CentOS/RHEL 7 as active directory client)?

Realmd provides a simple way to discover and join identity domains. It configures Linux system...

 How to create partitions and file systems on DM-Multipath devices?

Device-Mapper Multipath (DM-Multipath) is a Linux native multipath tool, which allows you to...

 How to determine number of CPUs on Linux using command line?

A CPU is an acronym for the central processing unit. It is an essential part of a computer. The...

 How to disable avahi-daemon service in CentOS/RHEL?

The avahi-daemon Linux service runs on client machines to perform network-based Zeroconf service...

 How to disable PREAUTH permanently in CentOS/RHEL 7

1. Login to the server as root.   2. Take backup of the file /lib/systemd/system/sssd.service....

 How to disable rtkit-daemon in CentOS/RHEL?

As per package description, RealtimeKit is a D-Bus system service that changes the scheduling...

 How to disable the default apache “Welcome Page” in CentOS/RHEL 7

Disabling Apache Welcome Page   Method 1: removing/renaming Welcome Page   1. In order to...

 How to disable “Alt+Ctrl+Del” causing system reboot in CentOS/RHEL 7?

In CentOS/RHEL 7, /etc/init/control-alt-delete.override no more works to override the key...

 How to enable SFTP Logging without chroot in CentOS/RHEL?

Secure File Transfer Protocol (SFTP) is a great tool for performing secure file transfers. This...

 How to exclude a file/directory from auditd rules?

In order to allow users to see what is going on, auditd can record all the audit-related events...

 How to find Intel NUC BIOS version and model on Linux

Find out BIOS version, run: # dmidecode | less $ sudo dmidecode | less   How to check BIOS...

 How to find the commands run by user before reboot in CentOS/RHEL?

Installing psacct (process accounting)   The psacct service is responsible for starting and...

 How to find the disk space allocated in Linux (CentOS /Red Hat .. . )

If the home directory, say /home, is a filesystem (mount point), then you could use df. If it's...

 How to find which specific ethernet device corresponds to a specific port on a multi-interface network card in CentOS/RHEL?

Method 1: If you only have remote access to the server If the server’s management module (such...

 How to hide files and directories in Linux

I am a new Linux user. How do I hide files and directories in Linux operating systems using the...

 How to install and configure ABRT (Automatic Bug Reporting Tool) in CentOS/RHEL?

ABRT (Automatic Bug Reporting Tool), is a set of tools that help users detect and analyze...

 How to install and configure “setroubleshootd” on CentOS/RHEL?

SELinux (Security Enhanced Linux) provides mandatory access control to the Linux operating...

 How To Install Elasticsearch, Logstash, and Kibana (Elastic Stack) on CentOS 7?

The Elastic Stack — formerly known as the ELK Stack — is a collection of open-source software...

 How to Manually Modify the GRUB parameters in CentOS/RHEL 7 before Booting?

An incorrect configuration in /etc/grub2.conf or  /boot/grub2/grub.cfg can cause CentOS/RHEL 7 to...

 How to modify the UUID of a Volume Group (VG) or Physical Volume (PV) in CentOS/RHEL?

The device node name of a disk (/dev/sda, /dev/hda, /dev/vda, etc.) may change in some...

 How to monitor /etc/shadow and /etc/passwd file for changes with Auditd?

System auditing is a very important task that should be a part of every server. It allows us to...

 How to monitor the Mounting/Umounting of Mount Points Using Auditd on CentOS/RHEL 6,7?

One of the best things about auditd is that it is tightly integrated with the kernel, so it gives...

 How to monitor time changes using auditd in CentOS/RHEL?

Auditing can provide accountability by tracing the actions of a user or process. It can state...

 How to override content type with Nginx web server

Use the following curl command: curl -I url curl -I curl -I...

 How to Run a Script When USB Devices Is Attached or Removed Using UDEV?

The post outlines steps to create UDEV rules that run a specific script when a USB device is...

 How to send Audit Logs to Remote Rsyslog Server in CentOS/RHEL 6,7?

 The following are the steps for direct audit logs of a remote rsyslog server on a CentOS/RHEL...

 How to set custom device names using udev in CentOS/RHEL 7?

There could be a requirement from client to have custom device names such as /dev/asmdisk01 for...

 How to set/disable banner message (MOTD) for a specific user in CentOS/RHEL?

To disable the MOTD or the banner message, only for a specific user in CentOS/RHEL 7.  Solution:...

 How to Start/Stop and Enable/Disable process accounting (psacct)?

The psacct service is responsible for starting and stopping process accounting at system boot...

 How to test port connectivity using nc utility in CentOS/RHEL?

The nc utility, which is also called netcat, comes in very handy when you want to test TCP/IP...

 How to use auditd to monitor a file deletion in Linux?

cThe auditd service can be a perfect tool to investigate such file deletion issues. The post...

 How to use auditd to monitor a specific SYSCALL?

A SYSCALL happens whenever a user executes a command that requests that the Linux kernel provide...

 How to Verify if ALUA Mode is Enabled on a LUN in CentOS/RHEL

ALUA stands for Asymmetrical Logical Unit Access. Midrange arrays usually have an internal...

 Input/Output Errors During XFS Filesystem Access In CentOS/RHEL 7

The Problem While accessing a directory mounted on XFS filesystem, it is throwing Input/Output...

 Install Google Chrome 73 on CentOS 7 using yum command

CentOS 7 install Google Chrome   Use wget command to grab Google Chrome 73 installer, run: $...

 Rsyslog : How to Send log files to remote server in CentOS/RHEL 6,7?

Need of a Centralized Rsyslog Server Every *NIX system has some sort of logging facility that...

 Swapon Fails To Mount Swap – Gives Invalid Argument Error

Symptoms will include (but are not limited to): After turning off swap or after a reboot, one...

 systemd alternatives to ‘service’ ‘chkconfig’ and ‘init ‘ commands in CentOS/RHEL 7

The systemctl command is used to interact with systemd and can be used to list systemd unit...

 Troubleshooting “connection refused” From Remote Servers in CentOS/RHEL 7 (Either Firewalld or iptables service issue)

This may be a case of Firewall on the local server dropping inbound connection attempts from...

 Unable To Extend LVM File System with Associated Snapshot in CentOS/RHEL

User is unable to Extend the LVM file system which has a snapshot, Error "Snapshot origin volumes...

 Why Does “/var/log/messages” Report Martian Packets?

A Martian packet as one which arrives on an interface where the interface does not use that...

 Why Does “netstat” Output Show Many Connections in CLOSE_WAIT Status?

Applications that handle a huge number of TCP connections, either as a server or as a client,...

 “Bad id for repo: My Repo, byte = 2” yum update error

Error While executing yum commands user is getting below error: # yum update Bad id for repo:...

 “iscsiadm” Discovery TimeOut With Two Or More Network Interfaces in CentOS/RHEL

This issue could occur when two or more Ethernet interfaces are connected to the same subnet or...

 “mlock failed: Cannot allocate memory” lvcreate command error in CentOS/RHEL 7

The issue is caused by the use_mlockall parameter in the LVM configuration file...