Configure CentOS to Sync with NTP Time Servers

 CentOS 7 / RHEL 7, Clusterweb, ClusterWeb, Leitura Recomendada, Linux, Profissional de TI  Comentários desativados em Configure CentOS to Sync with NTP Time Servers
ago 012019
 

Over the years, We’ve encountered many questions on how to correctly configure our Linux hosts to sync time to our enterprise NTP Servers.

So, We thought why not create an article that outlines in the simplest form possible the correct way to configure the NTP Client to synchronize with NTP Servers.

Sync CentOS with NTP Time Servers

First of all, we need to install the ntpd and ntpdate clients on our Linux host. I’m using CentOS, but it’s the same in Ubuntu and so forth.

# yum install ntp ntpdate
# systemctl start ntpd
# systemctl enable ntpd
# systemctl status ntpd

Now let’s run the following command to configure the NTP Servers.

# ntpdate -u -s 0.centos.pool.ntp.org 1.centos.pool.ntp.org 2.centos.pool.ntp.org

What we’re doing is telling the ntpdate to use an unprivileged port for outgoing packets with the -u switch and to write logging output to the system syslog facility using the -s switch.

Next let’s restart the ntpd daemon.

# systemctl restart ntpd

Now let’s check if NTP synchronization is enabled and running.

# timedatectl

And for the last, we will set the hardware clock to the current system time using the -w switch.

# hwclock -w

Congratulations! You’ve now successfully set your NTP client on CentOS.

jul 112019
 

There are multiple web interface for rTorrent like the most known ruTorrent. But all these alternatives haven’t a good UI. Here comes Flood, A modern web UI for rTorrent with a Node.js backend and React frontend.

The project is still work-in-progress but it’s already usable and features are added frequently.

You can find their Github here and more screenshots : https://github.com/jfurrow/flood

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Setup SMTP relay / smarthost with cPanel

 Clusterweb, ClusterWeb, Dns, Hospedagem, Linux, Profissional de TI, Proxy, Redes, Servidor de E-mail  Comentários desativados em Setup SMTP relay / smarthost with cPanel
abr 022019
 

Introduction

If you want or need to setup your mail server to send all outgoing mail to a specific server which will handle the delivery to the recipients you need to setup a SMTP relay or smarthost.

Prerequisites

  • You need to know the hostname of the SMTP server which is going to relay the mail for your mailserver, which is smtprelay.snel.com in our case
  • This article assumes that no authentication is necessary on the SMTP relay server
  • This article is written for cPanel with Exim
  • You need to have the login details of WHM ready

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Certbot

 Apache2, Clusterweb, ClusterWeb, Debian, Linux, SSL  Comentários desativados em Certbot
nov 072018
 

Install

Since it doesn’t seem like your operating system has a packaged version of Certbot, you should use our certbot-auto script to get a copy:

wget https://dl.eff.org/certbot-auto
chmod a+x certbot-auto

certbot-auto accepts the same flags as certbot; it installs all of its own dependencies and updates the client code automatically.

Certbot’s DNS plugins which can be used to automate obtaining a wildcard certificate from Let’s Encrypt’s ACMEv2 server are not available for your OS yet. This should change soon but if you don’t want to wait, you can use these plugins now by running Certbot in Docker instead of using the instructions on this page.

 

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How to install OpenVPN inside a jail in FreeNAS 9.2.1.6+ with access to remote hosts via NAT

 Clusterweb, ClusterWeb, Firewall, FreeNAS, Leitura Recomendada, Linux, Profissional de TI, Redes  Comentários desativados em How to install OpenVPN inside a jail in FreeNAS 9.2.1.6+ with access to remote hosts via NAT
maio 252017
 

Requirements

  • FreeNAS 9.10+
  • Domain updated by DDNS or a static IP
  • Internet access
  • Router forwarding of your port of choice (in my case 10011 UDP internal to 443 UDP external).
  • SFTP Client (Winscp, Transmit or plain scp)

Route all traffic?
If you want to route all traffic through the VPN Tunnel, be sure to read the Know This section

Overview
In this guide, we’ll do the server/client configuration as follows:

Server configuration:

  • Creating the Jail.
  • Optional: mounting local storage.
  • Installing OpenVPN inside the jail.
  • Creating all the certificates needed: the server root cert, the OpenVPN server cert and each of the client’s cert.
  • OpenVPN configuration file.
  • Firewall settings so NAT can work.
  • Registering OpenVPN as a service so it can start automatically with the jail.

Client configuration:

  • OpenVPN configuration file.
  • Certificate installation in client

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set 282015
 

Not to lose mails when main mail server is down, best solution is – mx backup server.

This is configuration to have backup mx server set up and running.

create /etc/postfix/relaydomains with contents:

then to create map for postfix – run:

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