Categories
Fedora Linux OS

Fedora 33: Problem with Broadcom Wifi Device

I am using Fedora workstation as my main OS on my laptop for many years, but usually I face a problem with my wifi device when I try to update my OS or change it. So, here is a solution to fix the problem: First, you have to determine your wifi device model by this […]

Categories
Apache CentOS Fedora Installation Linux OS RedHat Web Security

How to make Apache Web Server more secure

There are some known security issues that can make an Apache Web Server insecure. If using Apache as a web service is your approach, then you should scan your web server in first step. There are many tools to scan a web server. here we will use NIKTO. Nikto is a free tool which is […]

Categories
Web Security Wordpress

One way to Prevent DDOS attacks in WordPress

If you scan your WordPress site with wpscan tool, you would see a message like this: It means that a hacker can generate a DDOS attack on your host using this URL, cause this URL return a blank page and a 200 HTML Response Code. Also, this script will use a considerable amount of RAM […]

Categories
Database Oracle Security

Connection Encryption in Oracle Database

To encrypt connections between client and database server you have to set some parameters in sqlnet.ora file ($ORACLE_HOME/network/admin/sqlnet.ora) of server and client (you have to install oracle client on the client): server side: client side: the ENCRYPTION_CLIENT parameter can have one of these values: ACCEPTED : The client or server will allow both encrypted and […]

Categories
CentOS Linux Oracle Linux OS RedHat

How to setup a loadbalancer with HAProxy in RedHat 7

You have many options to install and configure a loadbalancer in RedHat 7. One of the best options is HAPorxy. To setup HAProxy, you have to download related RPM file and then install it: Then, you have to make changes in config file (/etc/haproxy/haproxy.conf): in this sample we have 4 servers as below: APP1: 192.168.1.2 […]

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CentOS Fedora Installation Linux Oracle Linux OS RedHat

Add New Disk to RedHat-based Linux without reboot

If you add a new disk to your OS, you won’t find this device in the device list (fdisk -l command). So you have two options to make it available: Reboot your machine Make the OS rescan all connected devices In operational environments, the first option is not considerable. So we have to choose the […]

Categories
Database MySQL

Change the Character Set & Collation of a table

To change the Character Set and Collation of a field of a table you have to use this query: if the table contains data, you have to update that data as follow:

Categories
Database Indexes Microsoft SQL Server

Rebuild and Reorganize all indexes within a database

If you want to REBUILD and REORGANIZE all your indexes in a database, you have to use this query: Rebuild: Reorganize:

Categories
Backup Restore Database Microsoft SQL Server

Backup/Restore Progress

To see the progress of Backup or Restore process you can use this query:

Categories
ASM Database Oracle

Database Startup Error: Fatal NI connect error 12547

If you see Fatal NI connect error 12547 error in alert log file of a Database in the middle of startup, and the database process couldn’t find DB PARAMETER FILE and CONTROL FILE, you have to check permissions,owner and group of these files: The permission of these files have to be 6751. The group of […]