Tag Archives: knockd

Links: 16 Aug

Technology:

  • Cloud server showdown: Amazon AWS EC2 vs Linode vs DigitalOcean. AWS performance sucks, Linode winner.
  • Pull mode in orchestration’s rising star, Ansible. Check also out the web interface — AnsibleWorks AWX
  • Learning from other disciplines, nice quote:

    I’ve seen several college of engineering departments that have a sign that says the equivalent of, “If you cheat in engineering classes, you will kill people later”. We don’t have that mindset yet with IT, but I think we should because eventually, we’ll be responsible for infrastructure that will kill people if we get it wrong.

  • knockd — a port-knock server. It listens to all traffic on an ethernet (or PPP) interface, looking for special “knock” sequences of port-hits. A client makes these port-hits by sending a TCP (or UDP) packet to a port on the server. When the server detects a specific sequence of port-hits, it runs a command defined in its configuration file. This can be used to open up holes in a firewall for quick access.
  • Here’s the example of why LISA conferences rock: 2007 paper On Designing and Deploying Internet-Scale Services. Must read for sysadmins.
  • How to automatically setup and keep ssh tunnel up with autossh, available from macports

Social:

  • Steven Fry, one of my all-time favourite actors and activists, wrote an open letter petitioning for moving Winter Olimpics 2014 from Russia to elsewhere, because of wilful LGBT community oppressions. On a related note, sexual orientation forms during prenatal period, influenced by hormone levels, and is therefore inborn feature. Read about it in Russian.