An http website is not encrypted. That is to say, the data comprising the site is not encrypted as it flows from the web server to the device (pc, phone, tablet) on which the user is viewing the page. Anyone able to “listen in” on the network could read that data, which is a security risk. An https web site is different. Data is encrypted. The web server encrypts each web page before transmission, and the user’s browser decrypts it, providing end-to-end protection from eavesdropping.
This article explains how to convert an existing basic website to https by obtaining a free digital certificate from Let’s Encrypt. It is based on a Raspberry Pi running the “Apache” web server, but will also work on other Linux systems. It is intended for home users and people running small-scale web sites, and as a learning aid. Continue reading →
Iptables is the name of the firewall built into the Linux kernel. It is also the tool used for firewall configuration. This post explains how to use iptables with a range of IP addresses and/or ports. It could be used, for example, to allow SSH traffic from a number of systems. Or to open up a range of ports with a single firewall rule.
The Linux firewall (part of the Netfilter project) is important on Internet facing systems, “edge” servers and “jump” boxes. Particularly when they do not sit behind another protective network element such as a load balancer or discrete firewall. For example, standaline cloud instances that are not part of a protected VPC infrastructure. Continue reading →