Category: Linux Administration

  • Gmail Rejecting Emails: Spamhaus Blacklisted Digital Ocean Mail Server

    Gmail Refusing Mail Server Emails

    I felt a shock when I saw a pile of undelivered emails from Gmail in my Inbox. All the bounced emails had following details. I did not know what would be the root cause so I went through couple of checks. Possible Root Causes for Gmail Rejecting Emails I went through following possible root causes…

  • Ubuntu 20: How to Enable TLS 1.0 and TLS 1.1 On Apache

    Ubuntu Apache Enable TLS 1.1 and 1.0

    When I migrated a site to a new Ubuntu 20 server, I faced an issue. I have a .Net application that is connecting to the my website. If the application is running on Windows 7, it cannot connect to the Website but if the application runs on Windows 10, it works. I figured out that…


  • Host ASP.NET Core 6 Application with Apache Using Webmin

    Install .Net Core 6 on Ubuntu 20

    If you are using Webmin to administer your Linux box, here are the steps to run ASP.NET Core 6 application with Apache. If you are interested in installing .Net Core 3, you may use this article. Prerequisites I assume that you have setup your server, Webmin and everything is up and running. Install .Net Core…


  • Uninstall .Net Core 3.1 From Ubuntu 18/20

    Uninstall .Net Core 3

    I had installed .Net Core 3.1 application on my Ubuntu 18/20 server. As the .Net Core 6 was released recently, I upgraded the source code to .Net Core 6. Instead of “upgrading” or co-hosting multiple .Net Core frameworks, I wanted to clean install .Net Core 6. In order to do that, I wanted to completely…


  • Digital Ocean Recovery Console Stuck in Caps Mode

    I am using Digital Ocean for hosting couple of Website including .Net Core Websites. For certain maintenance, I use Digital Ocean recovery console to login to the server. One day, accidentally something went wrong and console was stuck in caps mode. Trying to type in lower case would type in upper case and typing in…


  • Fixed: Virtualmin Keeps Disabling DKIM

    I wanted to enable DKIM for the multiple websites hosted on Digital Ocean using Webmin. I am using Digital Ocean DNS server and do not use the DNS server provided with Webmin. In fact, I keep the DNS service disabled. When I wanted to enable DKIM for emails, I went to Virual Min > Email…


  • How To Setup DKIM For Multiple Domains in Virtualmin

    I am hosting multiple domains using Webmin and wanted to setup DKIM for multiple domains. If you are using DNS server from Virtualmin, it would be easy to setup DKIM because Virtualmin takes care of not only enabling the DKIM for the domain but also setting up correct DNS record. I use 3rd party DNS…


  • Multiple Fail2ban.sqlite3 Files Consuming Too Much Disk Space

    I have recently upgraded my Digital Ocean droplet from 18.04 to 20.04 LTS. After the upgrade, I realized that droplet was consuming 80% of disk space. I have a basic droplet with 1GB RAM, 1 CPU, 25 GB hard disk to host multiple site and it is a good enough configuration for my need. But…


  • Upgrade Ubuntu Server 18.04.x to 20.04.01 LTS On Digital Ocean

    I was running Ubuntu Server 18.04 LTS version on Digital Ocean for hosting couple of Website. As Ubuntu 20.04.01 was recently released, I wanted to upgrade it so that I don’t have to worry about upgrading the server for next couple of years. I was using Ubuntu 18.04.x 64 bit that came built in with…


  • Webmin: 1 Package Available But Nothing to Update

    I am using Webmin to host multiple Websites. As a best practice, I am updating the packages whenever any update is available and reported on Webmin Admin Panel. From past couple of days, Webmin reported 1 package is available for update but when I click on the link, it showed “No packages available to be…