Zimbra Exporting all mail addresses Rumi, April 26, 2018April 26, 2018 Exporting all addresses (mailboxes, aliases and distribution lists) is a vital tool if you have a backup MX and only want it to accept email for valid recipients. One reason for that is to stop spammers who simply use a dictionary of common names to generate recipient email addresses which… Continue Reading
Set Up Nginx Load Balancing with SSL Termination Rumi, March 23, 2018 Nginx can be configured as a load balancer to distribute incoming traffic around several backend servers. SSL termination is the process that occurs on the load balancer which handles the SSL encryption/decryption so that traffic between the load balancer and backend servers is in HTTP. The backends must be secured… Continue Reading
Install webmin in Centos 7 Rumi, March 9, 2018 Step 1 — Installing Webmin First, we need to add the Webmin repository so that we can easily install and update Webmin using our package manager. We do this by adding a new file called /etc/yum.repos.d/webmin.repo that contains information about the new repository. Create and open this new file using… Continue Reading
Important Exim Commands Rumi, March 6, 2018November 6, 2018 To get a count of messages in the queue exim -bpc Print a listing of the messages in the queue (time queued, size, message-id, sender, recipient) exim -bp Print a summary of messages in the queue (count, volume, oldest, newest, domain, and totals): exim -bp | exiqsumm Print what Exim… Continue Reading
The SSL/TLS Handshake: an Overview Rumi, March 6, 2018 Obligatory SSL/TLS Handshake Graphic All SSL/TLS-related sites have their own version of a handshake diagram – here’s ours! (Click to enbiggen.) Let’s Clear Up Some Confusion, If We Can Some confusion about how SSL/TLS handshakes work is due to the handshake being only the prelude to the actual, secured session itself. Let’s try to… Continue Reading
Test your DNS using Dig, Nmap, Tcpdump Rumi, March 3, 2018March 3, 2018 For DNS resolution to succeed to 192.168.0.1, the DNS server at 192.168.0.1 will need to accept TCP and UDP traffic over port 53 from our server. A port scanner such as the nmap tool can be used to confirm if the DNS server is available on port 53 as shown… Continue Reading
Let’s Encrypt service with Pound server Rumi, February 5, 2018 In order to install Certbot on your server, follow the next steps: (make sure you have “git” installed on your system) $sudo apt-get install git (if not previously installed) $cd /opt $sudo git clone https://github.com/certbot/certbot Running the above commands will download the Certbot latest release from their git repo in… Continue Reading
Add Google Calendar to Thunderbird Mail Client Rumi, January 8, 2018 There are two plugins that must be installed: Lightning – the actual calendar plugin Provider for Google – allows bidirectional access to Google Calendar Install both of these plugins, from within Thunderbird (Menu button | Plugins | See all and then search for Lightning and then Provider for Google. Click Add to… Continue Reading
LEMP on Centos 6 Rumi, December 10, 2017 In this guide, we’ll walk you through installing all of these components (except for Linux, which is already installed as your OS when you create the server). Install the Extra Packages for Enterprise Linux Repository (or EPEL for short):sudo yum install epel-release Run a yum update to sync your packages with the… Continue Reading
Best Practices on Email Protection: SPF, DKIM and DMARC Rumi, August 20, 2017 Once we installed Zimbra Collaboration, we need to be aware of some additional configurations that will allow us to send emails to other Email systems with an improve Security, such Gmail, Hotmail, Yahoo!, etc. This Wiki article will show the different Email Protection resources that exists, depends of the volume… Continue Reading