IPTables config

So in my last blog post I promised that I would talk about iptables, and basically I have been a little lax in getting started with configuring the IPTables rules on the new servers I have set up. Now I mentioned that IPTables is quite powerful, and it can be if configured to be so, but I am using it as a basic firewall, so that should I accidental configure a service to listen on an external port it shan't be able too. On top of this I am going to set the rules up such that the three default chains drop packets that don't match any rules, meaning I am using them as first match allows the flow firewall, with a default drop.

posted at 08:49:59 PM on 24 Sep 2017 by Craig Stewart

Tags:sysadmin email project 

A new project, emails

So, when I started this blog I wanted to make it a record of my learning of new skills, particularly around electronics. That hasn't happened, and now that I have a new project to start it isn't about to start, this project is very much within my skill set (or at least it should be). A little background, I have been running my website, and email server, on my home connection for years, I got an internet connection with a company that was a good ISP for those who were a little more knowledgeable of networking and computers when I moved into my house. Back then I was a novice, but with an ISP a little more forgiving of allowing more advanced use of an internet connection I could host a website, and emails, without paying any extra money for a proper hosting solution. This has lead to me being the only person on my street that has a wireless internet connection during a power outage, but that is not really the point. Since then there has been a great deal of consolidation in the UK ISP market, and my ISP, PlusNet, was bought, some time ago, by BT. Until recently this wasn't really an issue, nothing much changed, BT kept PlusNet at arms length, but for some reason, now, PlusNet have chosen to add the block of IP addresses that the static IP for my connection is in to Spamhaus' Policy Block List. This marks my internet connection as not suitable for email hosting. So my new project is to move my emails into a proper hosting solution.

posted at 10:03:49 PM on 18 Sep 2017 by Craig Stewart

Tags:email project sysadmin 

Electronics, first steps.

So following on from my previous entry, where I decided I was going to build a cycle computer as an electronics project, to learn something new, I have purchased a RaspberryPi and some sensors to play with. (I purchased the stuff I thought I'd need from Pimoroni, a sheffield based company who give a proportion of their profits to the RaspberryPi foundation)

 So, I have started to have a look at what I can do.

 First things first, the RaspberryPi was bought with an SD card with Noobs pre-installed. I used this to install Rasbian (a port of my favourite Linux distribution optimised for the RaspberryPi). This was embarrassingly easy, or at least would have been if the small USB keyboard I was using wasn't faulty1. Easy solution I'll get a new one this weekend (probably).

Next the sensors, these came with little header pins that needed soldering to the boards (if not soldering wires directly to them, which I am not doing as I am using a breadboard to try things out before fixing things in stone) and I have learnt, I either need a hotter soldering iron and a considerable amount of practise, or a seriously massive amount more practise at soldering.

So in conclusion I need to spend more time on thinking about this stuff, and I need to spend more money.

1 This was not bought from pimoroni, but an old keyboard I had lying around.

posted at 09:15:29 PM on 21 Mar 2014 by Craig Stewart

Tags:fail soldering electronics learning stuff project 

Cycle Computer Concept

So, the thing that finally got me to start this blog is an idea that has been rattling around my head for a while

The idea started when I read this post on hackaday. What could I do with a distance sensor?

I started thinking about mounting it on my bike, so I could use it to know when cars get too close. This lead on to the idea for a cycle mounted computer as a sort of black box.

I used to have a simple cycle computer, but when the battery went flat I had a smart phone, which allowed me to download an app to turn the phone into a cycle computer. This actually does most of what I could possibly want from a cycle computer, and yet I find myself not using it. So from there I started seriously thinking about this idea. What would I need? What would I want it to do?

Lots of ideas for it rattled around my head, and the distance
sensor idea actually got abandoned fairly quickly (I can normally tell
when a car is too close without the aid of technology). The next problem is although I work with computers I haven't actually learned anything much about electronics, I'm a complete novice, so building a cycle computer, a portable power supply for it, and all the gubbins needed to get it working would be a challenge. But that's ok as I would have to learn some practical information about electronics, and learning can be fun.

So the stage I'm at now I still don't have a fully formed idea of what I want, or what I would need. I know I would need some form of speed sensor, and GPS would be nice, the GPS would be able to act as a speed sensor (as it does in my phone, when I actually use it). It needs some method of recording trips, and it needs to be simple to set up, turn on, and get running. A display of some sort would be good. Obviously some sort of power supply. A central way to control the lights would be a nice to have.

I think I'm going to cheat somewhat and base this project on a RasberryPi if I ever start it. But beyond that I'm actually not very far through deciding what I am going to build.

So going forward, the first task I need to set myself is to acquire a RasberryPi, and some toy electronics kits, and start playing, to see what I can do I suppose.

posted at 10:30:47 AM on 15 Mar 2014 by Craig Stewart

Tags:electronics project cycling ideas thinking rasberrypi