linux

Thursday, March 31, 2022

Securing Postfix With TLS

Encrypting data transfer over HTTP protocol is slowly becoming a common practice. Web browsers vendors, general security knowledge, and services like Let’s Encrypt help a lot. There are, of course, a lot of legacy systems with no encryption or an insecure configuration. However, in my opinion, the situation is a lot better than with the good, old, simple mail transfer protocol. So, if you have an SMTP service and it is not yet secured with TLS, you should do it, especially since it is not as straightforward as it seems initially.

The Problem With Nginx Add_header

I often have a problem using nginx’s add_header directive, especially with a complex configuration, including multiple virtual hosts. When I test the configuration, everything seems okay, and the nginx does not complain about any syntax. However, when checking the HTTP headers returned by the web server, it looks like it does not work.

How to Decrease the Size of Docker Images?

Creating new docker images based on some official Linux distributions or modifying existing ones increase their size. Sometimes, the difference between the new and the old ones dramatically exceeds the size of new packages or modifications. The reason behind that is mostly the way how images structure looks like and how Docker uses images and containers.