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 […]

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 […]

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 […]

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 […]

Database Export/Import (EXPDP/IMPDP) Oracle

IMPDP Errors: ORA-02374, ORA-12899

If the Character set of source and destination database are not equal, you will see below errors in the impdp log file: to solve this error, you have to restore the structure of tables first then you have to modify these fields with alter table command as below: finally, we you have to import data […]

Database Installation Oracle

Grid Infrastructure & Oracle Database 12c – Preinstallation tasks

To install Oracle Grid Infrastructure & Oracle Database on Oracle Linux 7, you need to prepare your OS. To do so, you have to follow these commands: First of all, you have to install required packages in the OS: then, you have to edit /etc/hosts file and add the appropariate record as bellow: you may […]