Category: CentOS

SSLH – Share A Same Port For HTTPS And SSH

Some Internet service providers and corporate companies might have blocked most of the ports, and allowed only a few specific ports such as port 80 and 443 to tighten their security. In such cases, we have no choice, but use a same port for multiple programs, say the HTTPS Port 443, which is rarely blocked. Here is where SSLH, a SSL/SSH multiplexer, comes in help. It will listen for incoming connections on a port 443. To put this more simply, SSLH allows us to run several programs/services on port 443 on a Linux system. So, you can use both SSL and SSH using a same port at the same time. If you ever been in a situation where most ports are blocked by the firewalls, you can use SSLH to access your remote server. This brief tutorial describes how to share a same port for https, ssh using SSLH in Unix-like operating systems.

Source: SSLH – Share A Same Port For HTTPS And SSH – OSTechNix
Related: Install sslh on Mac OSX

How to Keep Processes Running after SSH Logout in Linux

It happens many time that we try to access an app or content, but it ask for re-login or a popup which states your session is timed out. The session generally times out when content is kept idle and no transaction is performed. Many times “session_time” variable is set, which keeps active connection for time being. But what happens when session times out, a “SIGNUP” signal is sent to processes running in background as well as for processes that are children of the main process which are forced to terminate regardless of completion or partial completion of task. So how can we keep are the process running even after SSH Logout? In this article, I will explain how to keep the process running even after SSH is disconnected from a Linux terminal (Ubuntu 18.04 and CentOS 7).

Source: How to Keep Processes Running after SSH Logout in Linux (LinOxide)

Link: How to set up NTP server in CentOS

Network Time Protocol (NTP) is used to synchronize system clocks of different hosts over network. All managed hosts can synchronize their time with a designated time server called an NTP server. An NTP server on the other hand synchronizes its own time with any public NTP server, or any server of your choice. The system clocks of all NTP-managed devices are synchronized to the millisecond precision.

In a corporate environment, if they do not want to open up their firewall for NTP traffic, it is necessary to set up in-house NTP server, and let employees use the internal server as opposed to public NTP servers. In this tutorial, we will describe how to configure a CentOS system as an NTP server. Before going into the detail, let’s go over the concept of NTP first.

Full article here:
How to set up NTP server in CentOS (Xmodulo)

Link: How To Install Openfire On CentOS 7

Openfire is a real time collaboration (RTC) server licensed under the Open Source Apache License. It is also known as Jabber. It uses the only widely adopted open protocol for instant messaging, XMPP. The full name of XMPP is Extensible Messaging and Presence Protocol. It is a real-time communication protocol (which includes chat) based on XML. Installation and the management of Openfire is pretty simple.

It should be noted that with Openfire, no chat is possible yet. A client is needed: Openfire cannot be used alone, just like web servers need a browser.

In this tutorial we will see, how to install Openfire in a clean minimal installation of CentOS 7.

Full article here:
How To Install Openfire On CentOS 7 (Unixmen)

Link: Monitorix – An Open Source, Lightweight System Monitoring Tool For Linux

Monitorix is a free, Open Source monitoring tool that can be used to monitor as many services and system resources as possible. Unlike other monitoring tools, it is very simple to install, configure and monitor the systems. Initially, it was developed to support only the RPM based systems such as Red Hat, CentOS etc., but, later it is expanded its support to other distributions like Debian/Ubuntu, and BSD systems such as FreeBSD, NetBSD, and OpenBSD.

Full article here:
Monitorix – An Open Source, Lightweight System Monitoring Tool For Linux (Unixmen)

Link: Setting Up DNS Server On CentOS 7

DNS, stands for Domain Name System, translates hostnames or URLs into IP addresses. For example, if we type www.unixmen.com in browser, the DNS server translates the domain name into its associated ip address. Since the IP addresses are hard to remember all time, DNS servers are used to translate the hostnames like www.unixmen.com to 173.xxx.xx.xxx. So it makes easy to remember the domain names instead of its IP address.

This detailed tutorial will help you to set up a local DNS server on your CentOS 7 system. However, the steps are applicable for setting up DNS server on RHEL and Scientific Linux 7 too.

Full article here:
Setting Up DNS Server On CentOS 7 (Unixmen)