My quick notes regarding a SIM800L module on an inexpensive SIM800L EVB “SIM800LV2.2” carrier board from eBay. Communicates happily with a computer through a generic USB<>TTL converter, 5V logic levels and 5V power at 9600 baud. Carrier board includes a TTL level shifter and 2 diodes in series to drop the voltage from 5V to ~3.6V.
As you may know, .arpa domains are used for reverse DNS. But did you know that they are usable for forward DNS too?
During a new server deployment I’ve come across the need to use ECMP on Linux. Turns out it’s actually really simple to configure. Continue reading
In the past few months, quite a few people have asked me this question: “I bought a VPS from provider X, turned up a BGP session with them and my routes are all marked unreachable”. Today’s post will hopefully shed some light on what causes this phenomenon and how to deal with it.
OVH Public Cloud platform is based on OpenStack software. As such, it has an API using which many procedures can be automated. Today I will be showing how to automatically create whole server backups using snapshots.
Hurricane Electric’s free service Tunnel Broker allows one to set-up 6to4 tunnels in order to get IPv6 connectivity to IPv4-only sites. In addition to “regular” tunnels, where they assign you a random prefix from their ranges, they also support BGP tunnels. Today I will show you how to set one up and configure it on a Mikrotik device.
I was in a situation where I needed to implement a mail routing policy: Outgoing email from a specific domain gets routed through a relay (eg. Amazon SES) and all other goes directly.
Today we are going to compile nginx web server with naxsi WAF (Web Application Firewall), Google PageSpeed modules and HTTP/2 support.
Using nginx as a reverse proxy is very easy to do and there are many guides on the internet on this topic. However there’s not a lot of content regarding modifying proxied data on-the-fly. Here’s how to do it
I recently did a project where I needed to get post featured images from a WordPress site
using MySQL. Of course I wanted it to be efficient, which meant I had to do with
just a single SQL query to get the information I wanted.