How To Exclude Specific Packages from Yum Update in CentOS / RHEL Below I will show some examples how to exclude specific packages updates from manual yum update in Red Hat or CentOS. Yum is the primary tool for… Continue Reading
How To Enable Root SSH On Ubuntu and CentOS By default on Ubuntu server root SSH disabled for security reasons. That means you can login as user then use sudo to became root. In this article I will show… Continue Reading
5 Great Commands to Monitor Network Bandwidth on Linux Server Linux network traffic monitoring is one of the main parts of Linux troubleshooting. And can be done by many network monitoring utilities. In this article we will discover 5… Continue Reading
Docker Tutorial. Create Docker Image From Dockerfile In this docker tutorial I will show simple example how to create docker image from Dockerfile step by step. Also I will how build docker image from scratch. If Docker already installed… Continue Reading
6 Linux lsblk Command Examples lsblk useful terminal command for analysis Linux storage devices. lsblk – LiSt BLocK devices. Linux lsblk command lists information about all available or the specified block devices – disks. The lsblk command reads the… Continue Reading
Zimbra. Postfix_rbl_override.lmdb: No such file or directory How to fix Zimbra mail server error: lmdb:/opt/zimbra/conf/postfix_rbl_override is unavailable. open database /opt/zimbra/conf/postfix_rbl_override.lmdb: No such file or directory. To build missing postfix_rbl_override.lmdb file run postmap and zmprov. # /opt/zimbra/common/sbin/postmap /opt/zimbra/conf/postfix_rbl_override # /opt/zimbra/bin/zmprov mcf… Continue Reading
Useful Netcat Examples In this netcat tutorial you can see useful netcat examples to help you use this powerful tool. Netcat (nc – in short) can be called “Swiss army of knife” in Linux network terminal utilities. Netcat can be… Continue Reading
SSH Jump Host Jumphost or jumphost servers are intermediaries between the high security zone and the DMZ zones. And provide transparent control of devices in the DMZ zone. Of course jump host should be highly secured for preventing access to… Continue Reading
VsFTPd Passive Mode Enable If you don’t have already installed vsftpd on your Linux see article: How to Install vsftpd Server on CentOS. To enable vsftpd Passive Mode in Linux edit vsftpd config file: vsftpd.conf. Open with your favorite text… Continue Reading
How To Test Internet Speed On Linux VPS To get internet speed from command line Linux VPS we can use Python utility from SPEEDTEST – Speedtest-cli. Speedtest-cli is a script developed in Python programming language. Lets download SPEEDTEST utility from… Continue Reading