Developers Technical Tutorials

Using Ansible to Automate Deployment for Apps and IT Infrastructure

By Mike Goh July 3, 2020Developers Technical TutorialsDevOps, ServersNo Comments

Introduction Ansible is one of the few configuration management tools in the DevOps environment. It is an infrastructure automation platform used to deploy our applications and systems rapidly to enable continuous integration and continuous deployment. While there are others like…

Bash Script to Sync WordPress Docker Production to Demo

By Mike Goh June 6, 2020Developers Technical TutorialsCommand Line, DockerNo Comments

Introduction After we had upgraded a website from development to production status, we will need to put up a maintenance notice if we are required to make further changes. It is unpleasant to let visitors see the down-time or on-going…

Set Up DKIM, SPF and Reverse DNS to Improve Mail Deliverability

By Mike Goh May 14, 2020Developers Technical TutorialsNetwork, SecurityNo Comments

Introduction DomainKeys Identified Mail (DKIM) is a protocol that contributes to DMARC compliance and requests the sender origin to take responsibility for sent messages that can be verified by mailbox providers. Essentially, it enables the outbound domain to digitally sign…

Host Multiple Websites with jwilder nginx-proxy and letsencrypt-companion

By Mike Goh May 8, 2020Developers Technical TutorialsDocker, Web1 Comment

Introduction Two years ago, in 2018, I was introduced to Docker by a colleague of mine who was a brilliant programmer. Thus, I started my Docker journey on my own by reading tutorials online. I was developing a WordPress website…

How to Merge Server-side and Docker iptables Firewall Rules

By Mike Goh April 30, 2020Developers Technical TutorialsDocker, SecurityNo Comments

Introduction Docker is widely used to place applications in containers. One of the reasons why Docker is so popular is because of security thanks to its isolation capabilities. For example, it allows you to isolate applications from each other. Installing…

Host Website on IPv6 NAT VPS with Cloudflare DNS and NGINX

By Mike Goh April 26, 2020Developers Technical TutorialsServers, WebNo Comments

Introduction Cloud services like AWS, DigitalOcean and lesser-known VPS hosting providers sell VM (Virtual Machines). The annual price can range from $20 (less-known providers) to $70 for cloud services like AWS. All VM plans come with 1 dedicated IPv4 address…

How to Resolve iptables: No chain/target/match by that name

By Mike Goh April 24, 2020Developers Technical TutorialsCommand Line, SecurityNo Comments

Introduction If you encounter such error, it means that the CONFIG_NETFILTER module was not complied in your kernel. All VPS (virtual private server) that I owned from DigitalOcean, AWS, Google Cloud and other lesser-known host providers have it by default…

Change Port and Disallow Root Login to Secure SSH Server

By Mike Goh April 24, 2020Developers Technical TutorialsSecurity, ServersNo Comments

When you subscribe to a Linux VPS (Virtual Private Server) from any host providers, the default firewall rule is to accept all incoming connections to any ports hence you can connect via Port 22 using a SSH telnet client like…

How to Secure Server with Firewall using iptables

By Mike Goh April 23, 2020Developers Technical TutorialsSecurity, ServersNo Comments

iptables is a command-line firewall utility that allows a system administrator to configure the IP packet filter rules made possible by the Netfilter modules complied into the Linux Kernel. The rules are kept to a bare minimum on the firewall…

Using Ansible to Automate Deployment for Apps and IT Infrastructure

Bash Script to Sync WordPress Docker Production to Demo

Set Up DKIM, SPF and Reverse DNS to Improve Mail Deliverability

Host Multiple Websites with jwilder nginx-proxy and letsencrypt-companion

How to Merge Server-side and Docker iptables Firewall Rules

Host Website on IPv6 NAT VPS with Cloudflare DNS and NGINX

How to Resolve iptables: No chain/target/match by that name

Change Port and Disallow Root Login to Secure SSH Server

How to Secure Server with Firewall using iptables

Asus Router Setup – Wifi Settings

How to Resolve iptables: No chain/target/match by that name

Create Helpdesk Ticketing System with Google Apps Script

Host Multiple Websites with jwilder nginx-proxy and letsencrypt-companion