Install EPEL Repository on CentOS 7 (x64)

The simple one line command below will enable the EPEL repository on CentOS 7

rpm -Uvh http://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-2.noarch.rpm

Once ran you will see confirmation that it has been installed successfully, that’s it!

Notes

  • You can find out more about the EPEL repository here
  • If you don’t already have a server, I’d strongly recommend starting with DigitalOcean

Find Out Who Registered A Domain Name

The Internet is an amazing place where we can expand our knowledge – or – just look pictures of animals with funny captions, but have you ever wondered to yourself who owns that domain, who took the time to build that amazing website, see if a business is legit or maybe you just want to learn a new nerdy skill?

A domain name can be registered by anyone so long as its available and not registered to anyone else, and can be bought at anytime through hundreds, thousands or maybe millions of companies known as domain registrars. The job of a domain registrar is to take money and convert it into domain registrations as they are essentially the middle men between the domain registries (the top dogs of the domain world, the owners of the bit after the dot) and ourselves.

When a domain is registered, regardless of the registrar used, contact details will always need to be provided. These details form what’s known as the legal registrant and can be either a company or an individual who will legally own the name for however long it has been registered for.

That’s great but what next? Well here comes the juicy bit! All that information is kept in a global database known as the WHOIS database (pronounced “who is”) which is free to browse and will give an insight into any domain registration.

Querying WHOIS

The following guide will show you step by step how to query the WHOIS database for free with no special software required. To keep things simple I will be using a website that I created which has a built in WHOIS tool.

  • First things first we need to head to the WHOIS tool, click onto the following link or type it into your address bar directly: http://www.nerdtools.co.uk/whois/
  • Once the website loads you’ll see a box where it asks you to enter a domain name, enter the domain which you would like to query and press Enter or the “Let’s do this! >” button
    whois-query-1
  • After a few seconds you’ll be redirected to a new page that shows the domain details in a similar format to one shown below:
    whois-query-2
  • As  you can see from the screenshot above a lot of information is returned, so much that it doesn’t all fit on screen without scrolling but once you read through you will easily see who owns the domain, when it was registered, when it expires and other useful information

Notes

  • In the example above you can see no “Registrant’s address” is returned, this is because its a .UK domain and Nominet (the registry behind all .UK domains) allow the address to be hidden for any non-trading individuals, but with domains such as .COM, .NET, .ORG the information will always be available
  • Depending on the domain name things may look a little different to the one in the example
  • Any changes to a domains details can take up to 24 hours to show so things may not always be accurate
  • There are strict terms that need to be followed when it comes to using the information returned from a lookup and these can be found usually be found at the bottom – It’s not shown in the screenshot as it was so big, to see them click here and scroll down
  • Sometimes registrars offer a privacy package that will hide the registrants contact information and replace it with the registrars instead, if you see a domain like this that’s trading as a business stay well away as it could be up to no good!

Webmin 1.610 on CentOS 5.8 (x86)

The following commands can be used to install Webmin 1.610 on CentOS 5.8. Make sure you’re logged in as root and then follow the steps below.

Select a temporary directory to save the download to. We will only use the downloaded file once so it’s pointless keeping it.. free up space and put it in /tmp!

cd /tmp

Begin the download of Webmin using wget:

wget http://prdownloads.sourceforge.net/webadmin/webmin-1.610-1.noarch.rpm

Install Webmin by unpacking the archive:

rpm -Uvh webmin-1.610-1.noarch.rpm

Done! You can now login to your fresh installation of Webmin by heading to http://hostname-or-ipaddress:10000 using the root username and password.

Notes

  • You can download the file used in the example above by clicking here
  • If you don’t have a server to try this on I’d recommend DigitalOcean hands down – virtual servers start from $5 a month

WordPress & Spam: Key’s Solution

Recently I began to see an increase in malicious login attempts to my servers from bots (ie. automated attempts to login via FTP, POP/IMAP, SSH and so on) which gave me an idea for a new side-project on NerdTools known as the Bad Bots Intrusion & Spam Detection database.

After a few hours of developing a database was generating before my eyes of all the bad bots and their failed attempts, which then got me thinking, aside from using the database with a firewall can this be intergrated with WordPress to stop spam before its even posted?

A few more hours developing and I have now created two plugins which are listed in the WordPress extension directory. One is called NerdTools Bad Bots Spam Reporter which cleverly and annonymously reports the IP address of an author whenever a comment is classed as spam, and the other is called NerdTools Bad Bots Spam Defender which again annonymously screens every authors IP address against the database and if a match is found it won’t allow the comment to be saved.

Going a little deeper into the reporting plugin; when a comment is classed as spam the authors IP address is reported to the database but it won’t be entered straight away, our system will wait and see if any patterns form, if so it will then be entered and further comments will not be allowed.

It may seem madness having two seperate plugins to work as one but I didn’t want to force people into reporting comments if they don’t want to and vice versa with the defending plugin.

In terms of infrastructure the database is hosted on a high performance SSD server which has memcache enabled. Future plans include clustered servers for even greater performance.

Not bad for a few hours work!

 

 

 

 

Server Security Tips

Whenever I deploy a new server I always ensure that any flaws which I’ve picked up from my few years of server experience are fixed, leaving the new server as secure as can be and ready for use.

Below are a few tips for keeping your server as secure as can be:

  • Have a secure root password – Use something random and at least 8 characters long
  • Use non-default ports – Change the default port for services commonly targeted by bots or attackers such as SSH
  • Check your logs – Look for authentication failures and put the related IPs in a block or reject rule using iptables
  • Process users – Make sure processes have their own users and aren’t ran as root

More tips will be added once I remember them!

Unstick a LinkStation Disk Backup

Imagine this… you have two decent network attach storage boxes which regularly backup one to the other using a built in Disk Backup tool –  Brilliant huh, sounds almost like a nerdy dream! Now imagine part way through a backup you get a power cut or you just trip over the power cable ripping the plug out the wall… not to worry, things will pick up where they left off… unless those decent boxes are Buffalo LinkStations!

I first discovered this flaw a few weeks back when one of my nightly backups seemed to be taking longer than usual. I gave the box about a day or so to try and fix itself but it still kept saying that the disk backup was in progress and in the admin interface and I was unable to cancel or remove the backup, so it was pretty much stuck as you can see below:

stuck-backup

I headed to the official Buffalo support website which seemed to have a fix for this common problem – See for yourself below:

buffalo-stuck-disk-backup
Okay so you have to restore the box to factory defaults… no thanks! I can only assume that because the HS-DHGL is one of their older discontinued products they just can’t be bothered to make a firmware update as it’s not worth their time or effort, but the other option is to use SSH to edit a file which will force the backup to complete.

Getting Unstuck

The following guide will assume you have already enabled SSH and are logged in ready to go, if you haven’t yet enabled SSH see this post here.

  • First of all we need to locate the backup configuration file and this depends on the job number specified on the admin interface, in my case it was number 1 so we need to type in the following command to open the file in a text editor:
    • "vi /etc/melco/backup1"
  • You will now see the configuration file open, hit I (for indigo) on your keyboard to allow inserting of new text and change the line status=running to status=done
  • Hit the Escape key and then type :wq to save your changes and quit
  • Head back to the admin interface to the Disk Backup section and you’ll now see the backup showing as complete as seen below:
    job-complete
  • That’s it – The backup is unstuck, and we haven’t had to restore anything to factory defaults!

Notes

  • This has been tried and tested on the following models/firmware: HS-DHGL/v2.1
  • Finally, if you could let me know if you encounter any problems or can confirm if this works for other models I’d be grateful

Encrypted AES VPN tunnel between pfSense 2.3 and Ubiquiti EdgeRouter Lite

I recently retired my Draytek 2830 following a serious security flaw I discovered (that’s another post, stay tuned!) and took the plunge with a rather impressive looking Ubiquiti EdgeRouter Lite.

The other option was a rack mountable TP-Link TL-ER6020 although the maximum NAT throughput was only 180Mbps and it only had 128MB  DDR2 memory and no clear CPU specs, also the web interface looked tired and very restricted. Pound for pound the EdgeRouter was cheaper and has a better spec of anywhere up to and over 600Mbps, 512MB DDR2 memory and Dual‑Core 500 MHz, although it wasn’t rack mountable it was a no brainer with its modern web interface, also did I mention it can process 1 million packets per second?

The EdgeRouter also appeals to my inner nerd  (you can no doubt tell) as you can program it via web interface, command line or console connection and you can remove features you don’t need to boost performance. For example, it may only have 3 gigabit ports, but you can do whatever you like with them! In my case I have it configured as 1 WAN port and the other 2 ports are linked to two seperate LAN’s. I will write a full review when I get chance, but for now just take my word that it is the best router I have ever owned.

Anyway, to business!

Home Network

As before with the Draytek guide my home network is still double NAT’d but there isn’t a speed issue anymore. I do plan to eventually run everything via the EdgeRouter but first I need to install a few additional access points (I’m thinking a couple of airGateway-LR’s hidden in roof spaces will do, powered by PoE obviously!).

In the example below the home network subnet will be 192.168.100.x
and WAN address will be 1.2.3.4

Remote Network

The remote network is the same as before too – a pfSense machine sits at x.1 and deals with traffic to the local network.

In the example below the remote subnet will be 192.168.150.x and WAN address will be 5.6.7.8

Important

  • Each local area network must be on a seperate subnet, otherwise things can quickly get messy and conflict!
  • Make sure you use a secure pre-shared key, anything above 32 characters will do nicely and under no circumstances use the example key!
  • The example details below are fake, replace them with your own details if you want this to work

Configuring pfSense

The guide below lists only the parts you need to change, if the option isn’t listed then leave it as is. Anything to do with double NATing is in red, ignore this if your router is WAN facing.

Fairly straight forward, go to VPN > IPSec > Click Add P1

  • Enter the Remote Gateway as the WAN IP address of the EdgeRouter (or the Superhub in my case) 1.2.3.4
  • Enter a brieft description in the Description box – VPN to pfSense LAN
  • Select Peer identifer as KeyID tag then enter the WAN address of EdgeRouter (192.168.100.1) else leave as Peer IP address
  • Enter your pre-shared key in the Pre-Shared Key box – testing123
  • Set the DH Group to 14
  • Press Save

That’s your Phase 1 entry configured, now for Phase 2:

Go to VPN > IPSec > Click on Show Phase 2 Entries for Home

  • Enter Remote Network as the home network subnet – 192.168.100.0/24
  • Put a brief description in the Description box – Home
  • Set PSF Key Group to 14
  • Press Save and then hit Apply Changes

Finally, we need to create a firewall rule to allow traffic to pass over the VPN:

  • Go to Firewall > Rules > IPSec and click Add
  • Change Protocol to any
  • Enter a brief description in the Description box – Allow VPN Traffic
  • Press Save any hit Apply Changes

Configuring the EdgeRouter

First of all make sure you are running the latest firmware otherwise options may be missing and this may not go smoothly! Currently (March 2017) I’m running EdgeRouter Lite v1.9.1.

Configuring the EdgeRouter is pretty straight forward, you don’t need to do anything via command line or console (unless you really want to, knock yourself out!) – Go to VPN > IPSec Site-to-Site

  • First tick the box Show advanced options to show the encryption options
  • Under Global Options leave Automatically open firewall and exclude from NAT unless you want greater control over who can connect in
  • Under Site-to-site peers enter the Peer as the home WAN address – 5.6.7.8
  • Put a brief description in the Description box – Remote
  • In local IP enter any
  • For Encryption set AES-256
  • In Pre-shared secret enter the key set previously – testing123
  • Enter the Local subnet as 192.168.100.0/24
  • Enter the Remote subnet as 192.168.150.0/24

All being well you should end up with something like below:

Once everything is saved, head over to the pfSense IPSec Status page and hit connect if it hasn’t already established and  there you have it!

At this point you may be asking why did you uncheck the option to Automatically open firewall…, this is because I like to have greater control over what IP addresses are allowed access to my network.

To substitute this option I created a rule in the NAT section translating UDP port 4500 to the routers local IP address (192.168.100.1). In turn I set the Src Address Group of this rule to a list of predefined IP addresses, thus only allowing access to my networks and blocking the rest of the world.

 

 

 

Bypass Queue-it.com’s Online Queuing Service

For Black Friday 2014 Currys enlisted the Queue-it.com online queuing service to presumably create some form of buzz and make impatient paying customers even more eager to see what amazing deals they had – there really weren’t that many.

A few people at work were trying to get onto their website but found themselves not getting very far being constantly pushed to the back of the queue. As a joke I was asked to get around the queue and within two minutes I was on the Currys website.

I tried reverse proxying and modifying my browser user agent string but still found I was being redirected, meaning something in the websites source code was redirecting me. After a quick look through the source I notice some Javascript coming from the Queue-it.com domain. I disabled Javascript and was browsing instantly!

So, disable Javascript and skip that queue!

Notes

  • If you are regularly faced with Queue-it.com’s incredibly useful service consider installing browser plugin such as AdBlock or NoScript to block the entire queue-it.com domain and resume happy browsing

 

Connect Directly to SunLuxy Camera Streams

For a while now I’ve used a cheap SunLuxy H.264 DVR as the heart of the CoopCam project and initially couldn’t get a direct link to the camera stream so had to screen captured the bog standard web interface using VLC and break the feed down into separate streams but recently after a fair bit of trial and error I discovered a much easier solution!

I had researched on and off for months, went through masses of trial and error with various software and ultimately found no solution but after being inspired again I headed to the DVR’s web interface to start from scratch. I stumbled across source code in a file called /js/view2.js that constructs an RTMP:// address to show live camera feeds through the web interfaces flash player – See snippet of code below:

dvr_viewer.ConnectRTMP(index, "rtmp://" + location.host, "ch" + index + "_" + (dvr_type=="main"?"0":"1") + ".264");

After removing the jargon the link came out as rtmp://dvraddress:port/ch#_#.264 with the first number being the channel you want to connect to (starting at 0) and the second being the stream (substream being 1 and main being 0)

I headed to VLC player, selected Open Network Stream and entered the following:

rtmp://192.168.0.100:81/ch0_0.264

Broken down you can see my DVR is on the local network as 192.168.0.100 at port 81  and that I wanted to view channel 1’s main stream, low and behold after a few seconds the camera started to play!

Notes

  • To convert the stream to something more useful you could use rtmpdump and ffmpeg on Linux systems – I’ll write another guide about that shortly
  • If you do something wrong and overload the DVR then you’ll hear a beep as the box reboots
  • If this works for you please comment your DVR make and model

Upgrade Windows Phone 8.0 to 8.1 Before Main Release Using Developer Preview

Recently I lost my smartphone and after lots of searching decided to give up and buy a new phone. As I only really use my phone for checking emails, a little remote desktop access and the odd bit of mobile banking I didn’t need anything overkill and I fancied a change from Android so I went for a Windows based Nokia Lumia 520.

The Lumia 520 can be picked up for £69.00 on O2 pay as you go (as of 01/07/2014, see here) but I paid a little extra and got mine the same day. I was initially blown away by the Windows Phone operating system as it was better than expected and I couldn’t find any flaws. I’d setup my email, installed the mobile banking app and so on which lead me to my final task which was to install the Remote Desktop app. You’d think this would be a straight forward task installing a Microsoft product on something Microsoft powered but no, when heading to the Microsoft Store on the phone the Remote Desktop app wasn’t showing so I searched the Microsoft Store online and it came up saying that it wasn’t compatible with the Windows Phone 8.0 operating system that was currently on the phone.

I had three options, to cry in the corner, wait for the update to be released or to try upgrade the phone manually. After a little research the update was said to be released within the “…first two weeks of July…” but there was no exact date and I just couldn’t wait.

After more research it turns out that you can use a free app called Preview for Developers which allows you to basically get the update there and then instead of having to wait.

Upgrading Windows Phone 8.0 to 8.1

Below you’ll find a guide on how to upgrade the Windows Phone operating system. Please note that any changes you do here are irreversible and this will no doubt void your warranty.

  • First things first we need to create a free account with Microsoft’s App Studio using the link found here as this will give you access to the developer previews service and give you the magical updates – I used my main Microsoft account that’s linked to the phone to keep things simple
  • Once you’ve created the account go to Microsoft Store on the phone, search Preview for Developers and install the app
  • Once the app has installed launch it and you will be asked to accept the terms and conditions and login using the account details created previously
  • Next you’ll see information about what the app does and so on, all we need to do here is tick the box next to Enable Preview for Developers and press done
  • Now that’s enabled head to Settings > phone update and press check now and then follow the on screen instructions – You may need to repeat this process several times as it took me two updates to prepare the phone before the update to Windows 8.1 was offered
  • After a little while you will now be running Windows 8.1! – You can check this by viewing Settings > about > more information under the OS version heading

Notes

  • Make sure your phone is fully charged before attempting any updates as things could seriously go wrong otherwise!
  • As with anything in development stages things may be a little buggy so be aware that you may stumble across the odd glitch every now and again
  • Although not tested I assume the same steps will work for phones other than the Nokia Lumia 520, if you can confirm this I’d be grateful