Tec Bar » Linux

Install Sendmail Server on CentOS

James — Thu, 08 Sep 2016 03:27:29 +0000

Installing Required Packages [crayon-6a0312ab003c9147873465/] Configure Sendmail Server Comment out below line in /etc/mail/sendmail.mc to allow receiving email from anywhere. [crayon-6a0312ab003d3972136781/] Add this line also in sendmail.mc above ‘MAILER’ option [crayon-6a0312ab003d8510261066/] Add your PC’s full hostname in this file. [crayon-6a0312ab003dd702727174/] Recompile … Continue reading →

The post Install Sendmail Server on CentOS appeared first on Tec Bar.

Configure SSH Key-Based Authentication

James — Thu, 21 Apr 2016 05:56:31 +0000

SSH with key based authentication allows you to log on different servers via the personal private key on all servers, needing not to remember several passwords. SSH key pairs are two secure keys that can be used to authenticate a … Continue reading →

The post Configure SSH Key-Based Authentication appeared first on Tec Bar.

Drop Cache in Linux

James — Sat, 26 Dec 2015 23:36:18 +0000

Since kernel 2.6.16, a utility has been provided to allow the system to drop the page cache and/or inode and dentry caches on command, which can help free up a lot of memory. To use /proc/sys/vm/drop_caches, just echo a number … Continue reading →

The post Drop Cache in Linux appeared first on Tec Bar.

Problem: unable to execute /bin/rm: Success

James — Wed, 21 Oct 2015 21:37:19 +0000

In Linux environment, when you want to delete the files under one directory, you might see: “sudo: unable to execute /bin/rm: Success” Reason: too many files under the directory Solution: sudo find . -name ‘*’ -exec rm {} \;

The post Problem: unable to execute /bin/rm: Success appeared first on Tec Bar.

RAID 1 Repair on Linux

James — Sun, 27 Sep 2015 19:44:57 +0000

The disks in RAID 1 array may fail at any time. Situation: One day morning, a message may show up A Fail event had been detected on md device /dev/md0. It could be related to component device /dev/sda1. Faithfully yours, … Continue reading →

The post RAID 1 Repair on Linux appeared first on Tec Bar.

Add Email Account in your Linux Server

James — Thu, 24 Sep 2015 19:22:38 +0000

Assuming email server (for example, sendmail) is installed. Step 1: add an entry to /etc/mail/virtusertable like: user@domain.com user Step 2: create a normal user in the system. # sudo useradd user -s /sbin/nologin (It is not necessary to have a … Continue reading →

The post Add Email Account in your Linux Server appeared first on Tec Bar.

Delete all files within a directory that are older than 3 days

James — Fri, 19 Jun 2015 17:27:26 +0000

[crayon-6a0312ab01a7e486741202/] or [crayon-6a0312ab01a85324247160/]

The post Delete all files within a directory that are older than 3 days appeared first on Tec Bar.

Deny visitors by IP address using Apache .htaccess file

James — Mon, 20 Apr 2015 18:58:05 +0000

.htaccess is a configuration file for use on web servers running the Apache Web Server. In post “Block IP Address on CentOS / Redhat“, it provides one way to block IP address while .htaccess provides a different way to deny … Continue reading →

The post Deny visitors by IP address using Apache .htaccess file appeared first on Tec Bar.

Identify Who Logged in Your Linux System

James — Sat, 28 Mar 2015 00:35:11 +0000

There are several methods to identify who logged in your Linux system. 1. See who is logged on [crayon-6a0312ab01dfa540522694/] 2. Print effective username you are using [crayon-6a0312ab01e01582640795/] or use “who am I” [crayon-6a0312ab01e06058105643/] 3. Get the user login history [crayon-6a0312ab01e0b543086673/] … Continue reading →

The post Identify Who Logged in Your Linux System appeared first on Tec Bar.

List Open Ports and the Associated Process on CentOS / Redhat

James — Wed, 18 Mar 2015 22:43:55 +0000

Use the following commands to list the open ports. sudo netstat -ltn Use the following commands to list the open ports and the associated process / program name sudo netstat -lptun Quick way to find if a port is open … Continue reading →

The post List Open Ports and the Associated Process on CentOS / Redhat appeared first on Tec Bar.